The term is a straightforward descriptive phrase from Middle English, constructed entirely from native Old English components. It follows a common English syntactic pattern for specifying age or temporal status, similar to constructions like "man-of-war" or "jack-of-all-trades." The logic is purely literal: an animal that is "young of the year" is one born within the current annual cycle. Its specialized application in fields like ichthyology and wildlife biology demonstrates how transparent, vernacular phrases can become standardized technical terminology without undergoing morphological fusion or borrowing from classical languages.

This is a fixed compound phrase, not a single word formed from classical morphemes. It is an English descriptive term composed of common words: 'young' (Old English geong), 'of' (Old English of), 'the' (Old English þē), and 'year' (Old English gēar).