Collateral adjective
A collateral adjective is an adjective that is identified with a particular noun in meaning, but that is not derived from that noun. For example, the word "bovine" is considered the adjectival equivalent of the noun "cow", but it is derived from a different word, which happens to be the Latin word for "cow". Similarly, "lunar" serves as an adjective to describe attributes of the Moon; "moon" comes from Old English "mōna" "moon" and "lunar" from Latin "luna" "moon". The adjective "thermal" and the noun "heat" have a similar semantic relationship. As in these examples, collateral adjectives in  English very often derive from the Latin or Greek translations of the corresponding nouns. In some cases both the noun and the adjective are borrowed, but from different languages, such as the noun "air" (from French) and the adjective "aerial" (from Latin). The term "collateral" refers to these two sides in the relationship. In English, most ordinal numbers sound like their cardinal numbers, such as the ordinal 3rd (third) sounding like the cardinal number 3 (three), 4th (fourth) sounding like 4 (four), 10th (tenth) sounding like 10 (ten), 117th (one-hundred seventeenth) sounding like 117 (one-hundred seventeen), etc. However , 1st (first) and 2nd (second) sound unfamiliar to their cardinal counterparts 1 (one) and 2 (two). This is because these two ordinal numbers were derived from different roots, with "first" being derived from the Proto-Indo-European root meaning "forward", and "second" deriving from the Latin word "secundus", meaning "following". The phenomenon of ordinal numbers being collateral adjectives of cardinal numbers is common in the Sinospheric languages, including Japanese, Korean, and Vietnamese. For example, Japanese usually use Sino-Japanese numerals (words for numbers based on the Chinese language) for measure words that use ordinal numbers. Since Japanese, much like Chinese , doesn't have any inflections that indicate number, it uses measure words alongside a number to determine amounts of things. The numerals 1, 2, 3, 5, 6, 8, 9, and 10 usually use the pronunciation derived from Chinese (on'yomi), i.e. "ichi, ni, san, go, roku, hachi, kyū," and "jū" respectively. However, 4 can be pronounced using either its on'yomi "shi" or its native Japanese pronunciation (kun'yomi) "yon", depending on context, and likewise 7 can be pronounced either "shichi" or "nana", depending on context. Most measure words require the speaker to use the Sino-Japanese on'yomi numbers, e.g. 3 years is  sannenkan (3年間), 6 o'clock is "rokuji" (6時), 9 dogs is "kyūhiki no inu" (9匹の犬), 7 people is "shichinin" (7人), and 4 seasons is "shiki" (四季). However, there are some measure words (and even a select few numbers among certain measure words) that require the native kun'yomi numbers: 7 minutes is "nanafun" (7分), 4 apples is "yonko no ringo" (4個のリンゴ). Measure words that use native numbers include days of the month and "tsu", which is the generic measure word that roughly translates into "things". 1–10 are "hitotsu" (1つ)", futatsu" (2つ)", mittsu" (3つ), "yottsu" (4つ), "itsutsu" (5つ), "muttsu" (6つ), "nanatsu" (7つ), "yattsu  (8つ), kokonotsu" (9つ)", and tō" (10). While the measure word for people, "nin" (人), usually uses Sino-Japanese numbers, such as "sannin" (3人), "hachinin" (8人), and "jūnin" (10人), the measures for 1 and 2 people use the native numbers, which are "hitori" (1人) and "futari" (2人). Attributive usage of a collateral adjective is generally similar in meaning to attributive use of the corresponding noun. For example, "lunar rocket" and "moon rocket" are accepted as synonyms, as are "thermal capacity" and "heat capacity". However, in other cases the two words may have lexicalized uses so that one cannot replace the  other, as in "nocturnal view" and "night view", or "feline grace" but "cat food" (not *"cat grace" or *"feline food"). Collateral adjectives contrast with derived (denominal) adjectives. For the noun "father", for example, there is a derived adjective "fatherly" in addition to the collateral adjective "paternal." Similarly, for the noun "rain" there is derived "rainy" and collateral "pluvial," and for "child" there are derived "childish" and "childlike" as well as collateral "infantile" and "puerile." The term "collateral adjective" was coined by the "Funk and Wagnalls" dictionaries, but as they are currently out of print, the term has become rare. A  synonym sometimes seen in linguistics is "suppletive (denominal) adjective," though this is a liberal and arguably incorrect use of the word 'suppletive'.