# 乙

| 乙 | U+4E59, &#20057; CJK UNIFIED IDEOGRAPH-4E59 |
| ← 乘 [U+4E58] | CJK Unified Ideographs | 乚 → [U+4E5A] |
| ⼄ | U+2F04, &#12036; KANGXI RADICAL SECOND |
| ← ⼃ [U+2F03] | Kangxi Radicals | ⼅ → [U+2F05] |

## Translingual
### Han character

乙 (Kangxi radical 5, 乙+0, 1 stroke, cangjie input 弓山 (NU), four-corner 1771$_0$)
* Kangxi radical #5, ⼄.

#### Derived characters

* Appendix:Chinese radical/乙
* 亿, 忆, 㲸, 肊, 䎲, 釔(钇), 鳦, 氹, 艺, 朰, 戹, 穵
* 𫤾, 𠮙, 𫭖, 𫰆, 𡴭, 𢒼, 𢩧, 𣄻, 𣎷, 𪵖, 𤓱, 𥘆, 𥝎, 𬖋, 𦨇, 𧈝, 𮚲, 𮛁, 𬨖, 𪐘
* 𠫕, 𠮞, 𣄽, 𢖮, 𧰦, 𫚮, 𪸍, 𠀂, 𠧒, 𡴯, 𢩥, 𩁶, 𫘸, 𤴥, 𬸺, 𡆠

#### References

* Kangxi Dictionary: page 83, character 15
* Dai Kanwa Jiten: character 161
* Dae Jaweon: page 167, character 7
* Hanyu Da Zidian (first edition): volume 1, page 47, character 4
* Unihan data for U+4E59

## Chinese
### Glyph origin

Historical forms of the character 乙 :
| Shang | Western Zhou | Warring States | Shuowen Jiezi (compiled in Han) | Liushutong (compiled in Ming) |
| Oracle bone script | Bronze inscriptions | Chu slip and silk script | Small seal script | Transcribed ancient scripts |
| Oracle bone scriptj29982j29983j29984j29985j29986j29987j29988j29989j29990j29991j29992j29993j29994j29995j29996j29997j29998j29999j30000j30001j30002j30003j30004j30005j30006j30007j30008j30009j30010j30011j30012j30013j30014j30015j30016j30017j30018j30019j30020j30021j30022j30023j30024j30025j30026j30027j30028j30029j30030j30031j30032j30033j30034j30035j30036j30037j30038j30039j30040j30041j30042j30043j30044j30045j30046j30047j30048j30049j30050j30051j30052j30053j30054j30055j30056j30057j30058j30059j30060j30061j30062j30063j30064j30065j30066j30067j30068j30069j30070j30071j30072Bronze inscriptionsb20226b20227b20228b20229b20230b20231b20232b20233b20234b20235b20236b20237b20238b20239b20240b20241b20242b20243b20244b20245b20246b20247b20248b20249b20250b20251b20252b20253b20254b20255b20256b20257b20258b20259b20260b20261b20262b20263Small seal scripts10940Transcribed ancient scriptsL26039L26040L26041L26042L26043L26044L26045L26046L26047L26048L26049 |||||
| References: Mostly from Richard Sears' Chinese Etymology site (authorisation), which in turn draws data from various collections of ancient forms of Chinese characters, including: Shuowen Jiezi (small seal), Jinwen Bian (bronze inscriptions), Liushutong (Liushutong characters) and Yinxu Jiaguwen Bian (oracle bone script). |||||
| | Old Chinese |
| 劜 | *qreːd |
| 札 | *sqriːd |
| 扎 | *sqriːd |
| 蚻 | *ʔsriːd |
| 紮 | *ʔsriːd |
| 軋 | *qriːd |
| 圠 | *qriːd |
| 穵 | *qriːd, *qʷriːd |
| 挖 | *qʷriːd |
| 鳦 | *qriːd, *qrid |
| 耴 | *ŋrid, *teb |
| 乙 | *qriɡ |
| 肊 | *qrɯɡ |
Unknown. Different ancient texts propose different origins.
* Pictogram (象形) – a developing plant (Shuowen).
* Pictogram (象形) – the intestine of a fish (Erya).
* Pictogram (象形) – the gill bone of a fish (Liji Zhengyi (《禮記正義》)
The character should not be confused with 𠃉 > 鳦.

### Etymology 1
#### Pronunciation

* Mandarin
    (Standard)
       (Pinyin): yǐ (yi$^3$)
       (Zhuyin): ㄧˇ
    (Chengdu, Sichuanese Pinyin): yi$^3$
* Cantonese (Jyutping): jyut$^3$ / jyut$^6$
* Hakka
    (Sixian, PFS): yet / yat
    (Meixian, Guangdong): yad$^5$
* Northern Min (KCR): ĭ
* Eastern Min (BUC): ék
* Puxian Min (Pouseng Ping'ing): ih$^6$
* Southern Min
    (Hokkien, POJ): it
    (Teochew, Peng'im): ig$^4$
* Wu (Shanghai, Wugniu): $^7$iq
* Mandarin
** (Standard Chinese)
*** Hanyu Pinyin: yǐ
*** Zhuyin: ㄧˇ
*** Tongyong Pinyin: yǐ
*** Wade–Giles: i$^3$
*** Yale: yǐ
*** Gwoyeu Romatzyh: yii
*** Palladius: и (i)
*** Sinological IPA : /i²¹⁴/
** (Chengdu)
*** Sichuanese Pinyin: yi$^3$
*** Scuanxua Ladinxua Xin Wenz: i
*** Sinological IPA : /i⁵³/
* Cantonese
** (Standard Cantonese, Guangzhou–Hong Kong)
*** Jyutping: jyut$^3$ / jyut$^6$
*** Yale: yut / yuht
*** Cantonese Pinyin: jyt$^8$ / jyt$^9$
*** Guangdong Romanization: yud$^3$ / yud$^6$
*** Sinological IPA : /jyːt̚³/, /jyːt̚²/
* Hakka
** (Northern Sixian, incl. Miaoli)
*** Pha̍k-fa-sṳ: yet
*** Hakka Romanization System: ied$^ˋ$
*** Hagfa Pinyim: yad$^5$
*** Sinological IPA: /i̯et̚²/
** (Southern Sixian, incl. Neipu)
*** Pha̍k-fa-sṳ: yat
*** Hakka Romanization System: (r)iad$^ˋ$
*** Hagfa Pinyim: yad$^5$
*** Sinological IPA: /(j)i̯at̚²/
** (Meixian)
*** Guangdong: yad$^5$
*** Sinological IPA: /iat̚¹/
* Northern Min
** (Jian'ou)
*** Kienning Colloquial Romanized: ĭ
*** Sinological IPA : /i²⁴/
* Eastern Min
** (Fuzhou)
*** Bàng-uâ-cê: ék
*** Sinological IPA : /ɛiʔ²⁴/
* Puxian Min
** (Putian)
*** Pouseng Ping'ing: ih$^6$
*** Báⁿ-uā-ci̍: ih
*** Sinological IPA : /iʔ¹/
** (Xianyou)
*** Pouseng Ping'ing: ih$^6$
*** Sinological IPA : /iʔ²/
* Southern Min
** (Hokkien)
*** Pe̍h-ōe-jī: it
*** Tâi-lô: it
*** Phofsit Daibuun: id
*** IPA (Xiamen): /it̚³²/
*** IPA (Quanzhou): /it̚⁵/
*** IPA (Zhangzhou): /it̚³²/
*** IPA (Taipei): /it̚³²/
*** IPA (Kaohsiung): /it̚³²/
** (Teochew)
*** Peng'im: ig$^4$
*** Pe̍h-ōe-jī-like: ik
*** Sinological IPA : /ik̚²/
* Wu
** (Northern: Shanghai)
*** Wugniu: $^7$iq
*** MiniDict: ih$^入$
*** Wiktionary Romanisation (Shanghai): $^4$iq
*** Sinological IPA (Shanghai): /iɪʔ⁵⁵/
* Middle Chinese: 'it
Rime :
| Character | 乙 |
| Reading # | 1/1 |
| Initial (聲) | 影 (34) |
| Final (韻) | 質 (49) |
| Tone (調) | Checked (Ø) |
| Openness (開合) | Open |
| Division (等) | III |
| Fanqie | 於筆切 |
| Baxter | 'it |
| Reconstructions ||
| Zhengzhang Shangfang | /ʔˠiɪt̚/ |
| Pan Wuyun | /ʔᵚit̚/ |
| Shao Rongfen | /ʔiet̚/ |
| Edwin Pulleyblank | /ʔjit̚/ |
| Li Rong | /ʔjĕt̚/ |
| Wang Li | /ĭĕt̚/ |
| Bernhard Karlgren | /ʔi̯ĕt̚/ |
| Expected Mandarin Reflex | yi |
| Expected Cantonese Reflex | jat$^1$ |
* Old Chinese
    (Baxter–Sagart): /*qrət/
    (Zhengzhang): /*qriɡ/
Baxter–Sagart system 1.1 (2014) :
| Character | 乙 |
| Reading # | 1/1 |
| Modern Beijing (Pinyin) | yǐ |
| Middle Chinese | ‹ ʔit › |
| Old Chinese | /*qrət/ |
| English | 2nd heavenly stem |
| Notes for Old Chinese notations in the Baxter–Sagart system: * Parentheses "" indicate uncertain presence; * Square brackets "" indicate uncertain identity, e.g. *[t] as coda may in fact be *-t or *-p; * Angle brackets "<>" indicate infix; * Hyphen "-" indicates morpheme boundary; * Period "." indicates syllable boundary. ||
Zhengzhang system (2003) :
| Character | 乙 |
| Reading # | 1/1 |
| No. | 14921 |
| Phonetic component | 乙 |
| Rime group | 質 |
| Rime subdivision | 2 |
| Corresponding MC rime | 乙 |
| Old Chinese | /*qriɡ/ |
| Notes | 甲乙字收ɡ尾與燕乙字收d尾小分部有異 |

#### Definitions

乙
* The second of the ten heavenly stems (天干 (tiāngān))
* second; 2; B; II; beta (used for unnamed people or objects, to enumerate headings in a list, for grades, etc.)
    路人甲和路人乙 ― lùrén jiǎ hé lùrén yǐ ― passerby A and passerby B
       Tā fǎyǔ chéngjì dé le yǐ. [Pinyin]
       He got a B in French.
    乙肝 ― yǐgān ― hepatitis B
* (organic chemistry) eth-; ethyl
    乙烷 ― yǐwán ― ethane
* (literary, formal) one
       (gōngwén)...... Jiā yǐ fèn. [Pinyin]
       (In official letters) …added one copy.
       Yú běn diàn xiāofèi mǎn wǔbǎi yuán, jí kě huò zèng yōuhuìquàn yǐ zhāng. [Pinyin]
       Customers spending more than 500 dollars may obtain a coupon.
* a surname
* (Cantonese) This term needs a translation to English. Please help out and add a translation, then remove the text {{rfdef}}. (Classifier: 隻／只 c)
** 2023, 5m30s from the start, in 笑满岭南七十载：专访第三届广东文艺终身成就奖获得者黄俊英‎:
       gam$^2$ ngo$^5$ ng$^5$ ji$^6$ nin$^4$ jap$^6$ heoi$^3$ zyu$^1$ gong$^1$ jyut$^6$ kek$^6$ tyun$^4$ ge$^3$ si$^4$ hau$^6$, jat$^1$ zek$^3$ jyut$^3$ gam$^2$ gaa$^3$ zaa$^3$ wo$^3$. [Jyutping]
       (please add an English translation of this usage example)

#### Coordinate terms

* (Chinese heavenly stems) 天干 (tiāngān); 甲 (jiǎ), 乙 (yǐ), 丙 (bǐng), 丁 (dīng), 戊 (wù), 己 (jǐ), 庚 (gēng), 辛 (xīn), 壬 (rén), 癸 (guǐ)

#### Compounds

* 三氯乙烷
* 三氯乙烯 (sānlǜyǐxī)
* 丹鉛甲乙 / 丹铅甲乙
* 丹黃甲乙 / 丹黄甲乙
* 乙乙
* 乙力
* 乙士
* 乙夜 (yǐyè)
* 乙字庫 / 乙字库
* 乙帳 / 乙帐
* 乙干
* 乙弗
* 乙旃
* 乙更
* 乙榜
* 乙正
* 乙炔 (yǐquē)
* 乙烯 (yǐxī)
* 乙烷 (yǐwán)
* 乙科
* 乙第
* 乙等特考
* 乙腦 / 乙脑 (yǐnǎo)
* 乙覽 / 乙览
* 乙速孤
* 乙選 / 乙选
* 乙部
* 乙酸 (yǐsuān)
* 乙醇 (yǐchún)
* 乙醛 (yǐquán)
* 乙醚 (yǐmí)
* 乙鳥 / 乙鸟
* 令乙
* 勾乙 (gōuyǐ)
* 厶乙
* 圖乙 / 图乙
* 塗乙 / 涂乙
* 天乙
* 太乙
* 太乙壇 / 太乙坛
* 太乙宮 / 太乙宫
* 太乙數 / 太乙数
* 太乙爐 / 太乙炉
* 太乙神針 / 太乙神针
* 太乙舟
* 孔乙己
* 小乙
* 左乙
* 張甲李乙 / 张甲李乙
* 某乙
* 氯乙烯 (lǜyǐxī)
* 泰乙
* 獨乙 / 独乙
* 玄乙
* 甲乙
* 甲乙問 / 甲乙问
* 甲乙帳 / 甲乙帐
* 甲乙科
* 甲乙膏
* 白乙
* 聚乙烯 (jùyǐxī)
* 聚苯乙烯 (jùběnyǐxī)
* 苯乙烯 (běnyǐxī)
* 越鳧楚乙 / 越凫楚乙 (yuèfúchǔyǐ)
* 面乙
* 飛乙 / 飞乙
* 魚乙 / 鱼乙
* 鳧乙 / 凫乙
* 鴻乙滿紙 / 鸿乙满纸

#### Descendants

* → Zhuang: iet

### Etymology 2

Orthographic borrowing from Japanese 乙(おつ) (otsu).

#### Pronunciation

* Mandarin
    (Pinyin): yǐ (yi$^3$)
    (Zhuyin): ㄧˇ
* Mandarin
** (Standard Chinese)
*** Hanyu Pinyin: yǐ
*** Zhuyin: ㄧˇ
*** Tongyong Pinyin: yǐ
*** Wade–Giles: i$^3$
*** Yale: yǐ
*** Gwoyeu Romatzyh: yii
*** Palladius: и (i)
*** Sinological IPA : /i²¹⁴/

#### Definitions

乙
* (ACG, sometimes sarcastic) thank you for the hard work in (doing something)
    自演乙 ― zìyǎn yǐ ― (sarcastically) thank you for your hard work in staging this "drama"

### Etymology 3
#### Pronunciation

* Mandarin
    (Pinyin): yǐ (yi$^3$)
    (Zhuyin): ㄧˇ
* Cantonese (Jyutping): ji$^1$ / ji$^6$
* Mandarin
** (Standard Chinese)
*** Hanyu Pinyin: yǐ
*** Zhuyin: ㄧˇ
*** Tongyong Pinyin: yǐ
*** Wade–Giles: i$^3$
*** Yale: yǐ
*** Gwoyeu Romatzyh: yii
*** Palladius: и (i)
*** Sinological IPA : /i²¹⁴/
* Cantonese
** (Standard Cantonese, Guangzhou–Hong Kong)
*** Jyutping: ji$^1$ / ji$^6$
*** Yale: yī / yih
*** Cantonese Pinyin: ji$^1$ / ji$^6$
*** Guangdong Romanization: yi$^1$ / yi$^6$
*** Sinological IPA : /jiː⁵⁵/, /jiː²²/

#### Definitions

乙
* (music) Kunqu gongche notation for the note ti (7).
    Synonym: 𢒼 (yǐ) (Cantonese opera)
* (music) Cantonese opera gongche notation for the note low ti (7̣).
    Synonym: 一 (Kunqu)

#### Derived terms

* 亿 (yǐ)
* 𢒼 (yǐ)

### Etymology 4

From 笏.

#### Pronunciation

* Cantonese (Jyutping): fat$^1$ / wat$^1$
* Cantonese
** (Standard Cantonese, Guangzhou–Hong Kong)
*** Jyutping: fat$^1$ / wat$^1$
*** Yale: fāt / wāt
*** Cantonese Pinyin: fat$^7$ / wat$^7$
*** Guangdong Romanization: fed$^1$ / wed$^1$
*** Sinological IPA : /fɐt̚⁵/, /wɐt̚⁵/

#### Definitions

乙
* (Cantonese) Only used in 山雞乙／山鸡乙. (a place in Hong Kong)

## Japanese
### Kanji

(Jōyō kanji)

#### Readings

* Go-on: おつ (otsu, Jōyō)、おち (ochi)
* Kan-on: いつ (itsu)
* Kun: きのと (kinoto, 乙)、おと (oto, 乙)、かなでる (kanaderu, 乙でる)、めり (meri)

#### Compounds

* 乙(おと)子(ご) (otogo)
* 乙(おつ)種(しゅ) (otsushu)
* 乙(おつ)巡(じゅん) (otsujun)
* 乙(おと)女(め) (otome)
* 乙(おと)姫(ひめ) (otohime)
* 乙(いつ)夜(や) (itsuya), 乙(おつ)夜(や) (otsuya)

### Etymology 1

* Kanji in this term
* 乙
* おつ Grade: S
* goon
Originally from Middle Chinese 乙 (MC 'it), arising from the proper noun sense. Appears in texts from at least 833 CE.

#### Pronunciation

* (Tokyo) おつ [óꜜtsù] (Atamadaka – [1])
* IPA: [o̞t͡sɨ]

#### Proper noun

乙(おつ) • (Otsu)
* the second of the ten Celestial Stems
    Hypernyms: 天干 (tenkan), 十干 (jikkan)
    Coordinate terms: 甲, 乙, 丙, 丁, 戊, 己, 庚, 辛, 壬, 癸

#### Noun

乙(おつ) • (otsu)
* something B
** the second item of any ordered list
** (music) one tone lower than the note indicated by 甲 (kō, “something A”)
** (by extension from the musical sense) a lower, sonorous and moving sound or tone
** (noh theater) in noh musical accompaniment, a specific kind of muffled drum beat played by striking the head of the taiko drum and keeping the mallet pressed against the head
* (Kansai dialect, slang) a stupid person, someone who is slow on the uptake
* (rare, possibly archaic) the state or circumstances of a thing
* (rare, possibly archaic) dressing up in an odd fashion

### Etymology 2

* Kanji in this term
* 乙
* おつ Grade: S
* goon
By extension from the moving tone noun sense. Appears in texts from the late Edo period, in the early 1800s.

#### Pronunciation

* (Tokyo) おつ [òtsú] (Heiban – [0])
* IPA: [o̞t͡sɨ]

#### Adjective

乙(おつ) • (otsu) -na (adnominal 乙(おつ)な (otsu na), adverbial 乙(おつ)に (otsu ni))
* out of the ordinary, strange or unusual in an interesting or stylish way
* strange, odd, weird
** :ja:東海道中膝栗毛 (Tōkaidōchū Hizakurige, “Footing It along the Tokaido Road”, or “Shank's Mare”), serial published 1802-1814:
    ヲヤ弥(や)次(じ)さん、おつな手(て)つきをしておめへ何(なに)をする
       Oya Yaji-san, otsu na tetsuki o shite omē nani o suru
       Oy, Yaji, what do you think you're doing with your weird way of using your hands?

##### Inflection

Stem forms :
| Imperfective (未然形) | 乙だろ | おつだろ | otsu daro |
| Continuative (連用形) | 乙で | おつで | otsu de |
| Terminal (終止形) | 乙だ | おつだ | otsu da |
| Attributive (連体形) | 乙な | おつな | otsu na |
| Hypothetical (仮定形) | 乙なら | おつなら | otsu nara |
| Imperative (命令形) | 乙であれ | おつであれ | otsu de are |
| Key constructions ||||
| Informal negative | 乙ではない 乙じゃない | おつではない おつじゃない | otsu de wa nai otsu ja nai |
| Informal past | 乙だった | おつだった | otsu datta |
| Informal negative past | 乙ではなかった 乙じゃなかった | おつではなかった おつじゃなかった | otsu de wa nakatta otsu ja nakatta |
| Formal | 乙です | おつです | otsu desu |
| Formal negative | 乙ではありません 乙じゃありません | おつではありません おつじゃありません | otsu de wa arimasen otsu ja arimasen |
| Formal past | 乙でした | おつでした | otsu deshita |
| Formal negative past | 乙ではありませんでした 乙じゃありませんでした | おつではありませんでした おつじゃありませんでした | otsu de wa arimasen deshita otsu ja arimasen deshita |
| Conjunctive | 乙で | おつで | otsu de |
| Conditional | 乙なら（ば） | おつなら（ば） | otsu nara (ba) |
| Provisional | 乙だったら | おつだったら | otsu dattara |
| Volitional | 乙だろう | おつだろう | otsu darō |
| Adverbial | 乙に | おつに | otsu ni |
| Degree | 乙さ | おつさ | otsusa |

### Etymology 3

* Kanji in this term
* 乙
* おつ Grade: S
* goon
* Alternative spelling
* o2
Derived as aggressive clipping of お疲れ様です (otsukaresama desu, used as a kind of greeting at work, literally “that's honorable exhaustion (from hard work)”). The use of 乙 for the spelling is an example of phonetic ateji (当て字).

#### Pronunciation

* IPA: [o̞t͡sɨ]

#### Interjection

乙(おつ) • (otsu)
* (Internet slang) Clipping of お疲れ様です (otsukaresama desu).
    自演(じえん)乙(おつ)
       Jienotsu
       I appreciate your acting (a satire of someone who sock puppeting to praise himself)

##### Derived terms

* うp乙(おつ) (upotsu), うぽつ (upotsu)

### Etymology 4

* Kanji in this term
* 乙
* きのと Grade: S
* kun'yomi
Compound of 木 (Ki, “Wood”, one of the Five Elements) +‎ の (no, attributive marker) +‎ 弟 (oto, “younger brother”).

#### Pronunciation

* (Tokyo) きのと [kìnóꜜtò] (Nakadaka –)
* IPA: [kʲino̞to̞]

#### Proper noun

乙(きのと) • (Kinoto)
* the second of the ten heavenly stems
    Hypernyms: 天干 (tenkan), 十干 (jikkan)
    Coordinate terms: 甲, 乙, 丙, 丁, 戊, 己, 庚, 辛, 壬, 癸

### Etymology 5

* Kanji in this term
* 乙
* おと Grade: S
* kun'yomi
* Alternative spelling
* 弟
Cognate with the initial oto- in 劣る (otoru, “to be less than; to be younger than”), 落とす (otosu, “to drop something”). Also the first element in 弟 (otōto, “younger brother”).
First attested in the Kojiki of 712.
This is distinct from the initial oto- in 乙女(おとめ) (otome), which can instead be traced to an earlier woto- root, cognate with 復(を)つ (wotu).

#### Pronunciation

* IPA: [o̞to̞]

#### Noun

乙(おと) • (oto)
* [from 712] (archaic) a younger sibling
    Antonym: (older sibling, archaic) 兄 (e)
    Hyponyms: 弟 (otōto, “younger brother”), 妹 (imōto, “younger sister”)
* [from late 1500s] (archaic) the youngest sibling
    Synonym: 乙子 (otogo)
* [from late 1500s] (archaic) clipping of 乙娘 (oto musume) a young woman
* [from late 1500s] (archaic, Noh theater) clipping of 乙御前 (oto goze): a stock character in 狂言 (kyōgen) comic interludes, played as a plump and clumsy but earnest young woman
    Synonyms: おたふく (otafuku), おかめ (okame)

#### Prefix

乙(おと) • (oto-)
* applied to a noun denoting a person, or to a person's name:
** next, younger, youngest
** beautiful, beloved, cute, dear

### References

* 1 2 3 Shōgaku Tosho (1988) 国語大辞典（新装版） [Unabridged Dictionary of Japanese (Revised Edition)] (in Japanese), Tōkyō: Shogakukan, →ISBN
* 1 2 3 Matsumura, Akira, editor (2006), 大辞林 [Daijirin] (in Japanese), Third edition, Tokyo: Sanseidō, →ISBN
* ↑ Shinmura, Izuru, editor (1998), 広辞苑 [Kōjien] (in Japanese), Fifth edition, Tokyo: Iwanami Shoten, →ISBN
* ↑ “弟・乙”, in 日本国語大辞典 [Nihon Kokugo Daijiten]‎ (in Japanese), concise edition, Tokyo: Shogakukan, 2006

## Korean
### Hanja

乙 (eumhun 새 을 (sae eul))
* bird

### References

* 국제퇴계학회 대구경북지부 (國際退溪學會 大邱慶北支部) (2007). Digital Hanja Dictionary, 전자사전／電子字典.

## Middle Korean
### Particle

乙 (-ol)
* idu form of ᄋᆞᆯ (accusative case marker)
** 1395, 高士褧 (Go Sa-gyeong), 金祗 (Kim Ji), 大明律直解 (Daemyeongnyul Jikhae) [Correct Translation of the Great Ming Code]:本國乙背叛PWON.KWUK-ul POY.PANBetray his native country

## Old Korean
### Etymology 1

From a Late Middle Chinese pronunciation of 乙 (MC 'it), which lenited coda /-t/ to /-r/.

#### Phonogram

乙 (*-r)
* A consonantal phonogram denoting coda consonant *-r

##### Usage notes

Generally believed to have been pronounced as *-r, based both on internal evidence and the Chinese etymon. Old Korean 尸 (*-l) and 乙 (*-r) both merged unconditionally into *-l in Middle Korean, but the two phonograms were consistently distinguished in Old Korean until the late thirteenth century. Because Old Korean reconstructions are conventionally romanized using their Middle Korean reflex, the phonologically erroneous reconstruction *-l is often used as a shorthand.

### Etymology 2
#### Alternative forms

* 肹 (*-(u)r, *-hur)

#### Particle

乙 (*-(u)r)
* Accusative case marker
** 1120, King Yejong of Goryeo, “悼二將歌 (Doijang-ga)”, in 平山申氏系譜 (Pyeongsan Sin-ssi Gyebo) [Genealogy of the Pyeongsan Sin descent group]:主乙完乎白乎心聞*NIRIM-ur WOPOL-wo-SOLP-wo(n) MOSOm-onas for the heart that admired his lord

##### Usage notes

In Middle and Modern Korean, the allomorph taken by the accusative marker after a vowel may be 를 (-reul) instead of ㄹ (-l), especially in formal speech. This is the result of reduplication of the particle and is unlikely to have been present in Old Korean, although the phonologically opaque nature of the orthography makes it difficult to tell for sure.
In "Middle Old Korean", the late first-millennium stage of Korean represented by about a dozen mostly eighth-century poems, the accusative particle was consistently written with the phonogram 肹. 乙 has become dominant by the twelve poems of the tenth-century monk Gyunyeo, however, and 肹 is virtually not attested at all by the second millennium. There seems to be no semantic difference involved. Whether this represents a phonetic shift or simply a change in orthographic practice is unknown, although 肹 and 乙 had differing Middle Chinese initials.

##### Descendants

* Middle Korean: ᄋᆞᆯ/을 (-(o/u)l, accusative marker)
** Korean: -을 (-eul, accusative case marker)

### References

* ↑ Alexander Vovin, Old Korean and Proto-Korean *r and *l revisited
* ↑ 이승재 (Yi Seung-jae) (2000) “차자표기 자료의 격조사 연구 [chajapyogi jaryoui gyeokjosa yeon'gu, A study of case markers in Sinographic sources]”, in Gugeo gungmunhak, volume 127, pages 107—132
* ↑ 황선엽 (Hwang Seon-yeop) (2008) “삼국유사와 균여전의 향찰 표기자 비교 [samgugyusawa gyunyeojeonui hyangchal pyogija bigyo, A comparison of the orthography of the hyangchal of the Samguk yusa and the Gyunyeo-jeon]”, in Gugeohak, volume 51, pages 279—311

## Vietnamese
### Han character

乙: Hán Nôm readings: ất, át, ắc, ắt, hắt, ặc, lớt
* chữ Hán form of Ất.
** second of the ten heavenly stems
    Hypernyms: 天干, 十干
    Coordinate terms: 甲, 乙, 丙, 丁, 戊, 己, 庚, 辛, 壬, 癸
** Kangxi radical 5—‘second’, ‘fishing hook’

#### Compounds

* 乙丑 (Ất Sửu)
* 乙亥 (Ất Hợi)
* 乙卯 (Ất Mão)
* 乙巳 (Ất Tỵ)
* 乙未 (Ất Mùi)
* 乙酉 (Ất Dậu)

#### References

* Nom Foundation