The word 'yore' has a direct lineage from Old English, where 'geāra' meant "of years." This genitive plural construction was used adverbially in phrases like "in days of yore," essentially meaning "in times of (many) years past." Over time, this adverbial phrase solidified into a standalone noun referring to a distant, often nostalgically remembered, past. Its journey from a grammatical case form of "year" to an abstract concept of time long gone illustrates how specific linguistic structures can lexicalize into words carrying a poetic and temporal weight.

The word is a simplex form. It originates from the Middle English word 'yore', which itself comes from Old English 'geāra', the genitive plural form of 'gēar' (year). Its functional role is as a noun.