# -ко
## Bulgarian
### Etymology

Inherited from Proto-Slavic *-ъko and Proto-Slavic *-ьko (the later causing palatalization of preceding velars).

### Pronunciation

* IPA: [-kɔ] (never accented)

### Suffix

-ко • (-ko) m
* Forms diminutive forms of masculine nouns (including personal names):
    ‎ба́те (báte) + ‎-ко (-ko) → ‎ба́тко (bátko)
    ‎дете́ (deté) + ‎-ко (-ko) → ‎де́чко (déčko)
    ‎еж (ež) + ‎-ко (-ko) → ‎е́жко (éžko)
    ‎сняг (snjag) + ‎-ко (-ko) → ‎сне́жко (snéžko)
    ‎Ива́н / Йоа́н (Iván / Joán) + ‎-ко (-ko) → ‎Ива́нко / Я́нко (Ivánko / Jánko)
    ‎Дими́тър (Dimítǎr) + ‎-ко (-ko) → ‎Ми́тко (Mítko)
* Forms substantive nouns (including personal names), denoting carriers of a property, from of adjectives:
    ‎бо́рък (bórǎk) + ‎-ко (-ko) → ‎бо́рко (bórko) (adjectives in -ък lose the ending)
    ‎игри́в (igrív) + ‎-ко (-ko) → ‎игри́вко (igrívko)
    ‎сръ́чен (srǎ́čen) + ‎-ко (-ko) → ‎сръ́чко (srǎ́čko) (adjectives in -ен lose the ending)
    ‎сърди́т (sǎrdít) + ‎-ко (-ko) → ‎сърди́тко (sǎrdítko)
    ‎мил (mil) + ‎-ко (-ko) → ‎Ми́лко (Mílko)
    ‎вел(ик) (vel(ik)) + ‎-ко (-ko) → ‎Ве́лко (Vélko)
* Forms masculine agent nouns (including personal names) from verbs or participles:
    ‎дърдо́ря (dǎrdórja) + ‎-ко (-ko) → ‎дърдо́рко (dǎrdórko)
    ‎сека́ (seká) + ‎-ко (-ko) → ‎се́чко (séčko)
    ‎люби́м (ljubím) + ‎-ко (-ko) → ‎люби́мко (ljubímko)
    ‎присмеху́л се (prismehúl se) + ‎-ко (-ko) → ‎присмеху́лко (prismehúlko)

#### Related terms

* -чо (-čo) (< -ко (-ko) +‎ -е (-e, diminutive suffix))

## Macedonian
### Etymology

Inherited from Proto-Slavic *-ьko.

### Pronunciation

* IPA: [kɔ]

### Suffix

-ко • (-ko) m
* Suffix appended to words to create a masculine noun.
    ‎брат (brat) + ‎-ко (-ko) → ‎братко (bratko)
    ‎весел (vesel) + ‎-ко (-ko) → ‎веселко (veselko)
    ‎брбори (brbori) + ‎-ко (-ko) → ‎брборко (brborko)
    ‎трај (traj) + ‎-ко (-ko) → ‎Трајко (Trajko)

#### Derived terms
## Old Church Slavonic
### Suffix

-ко • (-ko)
* Forms correlatives of modality

#### Derived terms

како, тако, инако, онако, единако, сице

## Russian
### Etymology

Inherited from Proto-Slavic *-ьko.

### Pronunciation

* -ко: IPA: [kə]
* -ко́: IPA: [ˈko]

### Suffix

-ко or -ко́ • (-ko or -kó)
* Creates diminutives of normally neuter nouns and adverbs, normally having a colloquial register.
    ‎я́блоко (jábloko, “apple”) + ‎-ко (-ko) → ‎я́блочко (jábločko, “small apple”)
    ‎пи́во (pívo, “beer”) + ‎-ко́ (-kó) → ‎пивко́ (pivkó, “beer”)
    ‎се́рдце (sérdce, “heart”) + ‎-ко (-ko) → ‎серде́чко (serdéčko, “small heart; heart symbol”)
    ‎ведро́ (vedró, “bucket”) + ‎-ко (-ko) → ‎ведёрко (vedjórko, “small bucket, small pail”)
    ‎тихо́нько (tixónʹko, “quiet”) + ‎-ко (-ko) → ‎тихо́нечко (tixónečko, “very quiet”)
    ‎солове́й (solovéj, “nightingale”) + ‎-ко (-ko) → ‎солове́йко (solovéjko, “small nightingale”)

#### Usage notes

* The suffix is added to the stem of the word (i.e. minus its final vowel, if any). An epenthetic vowel often breaks up stem-final consonant clusters, and velars become palatals according to the Slavic first palatalization (both effects are due to the yer that occurred at the Proto-Slavic level). These effects can be seen in серде́чко (serdéčko, “small heart”), derived from се́рдце (sérdce, “heart”), and тихо́нечко (tixónečko, “very quiet”), derived from тихо́нько (tixónʹko, “quiet”), itself containing the same diminutive ending. (Specifically, starting from the stem *тихо́ньк-, a vowel is epenthesized, producing тихо́нек-, and the final velar is palatalized, producing тихо́неч-.) In general, the combination -ко + -ко produces -ечко (-ečko) or -очко (-očko).

#### Declension

$^△$Irregular.

#### Derived terms
## Serbo-Croatian
### Suffix

-ко (Latin spelling -ko)
* Suffix appended to words to create a masculine noun, usually denoting a negative feature.

## Ukrainian
### Etymology

Inherited from Proto-Slavic *-ьko.

### Pronunciation

* -ко: IPA: [ kɔ]
* -ко́: IPA: [ ˈkɔ]

### Suffix

-ко or -ко́ • (-ko or -kó) m or n
* Creates diminutives of normally neuter nouns and adverbs, normally having a colloquial register.
    ‎пи́во (pývo, “beer”) + ‎-ко́ (-kó) → ‎пивко́ (pyvkó, “beer”)
    ‎солове́й (solovéj, “nightingale”) + ‎-ко (-ko) → ‎солове́йко (solovéjko, “small nightingale”)

#### Usage notes

* The suffix is added to the stem of the word (i.e. minus its final vowel, if any). An epenthetic vowel often breaks up stem-final consonant clusters, and velars become palatals according to the Slavic first palatalization (both effects are due to the yer that occurred at the Proto-Slavic level). In general, the combination -ко + -ко produces -ечко (-ečko), -очко (-očko)