Collateral adjective

A collateral adjective is an adjective whose word origin is different from the noun it represents. English has many collateral adjectives from French, Latin, and Greek because many English words come from those languages. For example, the adjectives for the native English words "horse" and "moon" are "equine" and "lunar". "Equine" comes from the Latin "equus", and "lunar" comes from the Latin "luna" and so the study of horses is called "equine science", and the calendar for the moon is called the "lunar calendar".

Some nouns have both collateral and derived adjectives, whose origin is the same as the nouns that they represent. For example, "father" has the adjective "fatherly", from "fathe", but it also has the collateral adjective "paternal". from the Latin word "pater", which also means "father".