The word 'treasury' originates from the Latin 'thesaurus', meaning a hoard or storehouse of valuables, which itself was borrowed from the Greek 'thēsauros'. The term entered English via the Old French 'tresor', evolving into 'treasure'. The suffix '-y', derived from Old French '-ie', was added to form a noun denoting the place or institution associated with treasure. Thus, the literal concept of a "place for a hoard" evolved into the modern abstract meanings of a government finance department and any curated collection of prized items.

Structure: treasure (wealth) + y (noun suffix) "treasure" from Old French 'tresor', ultimately from Latin 'thesaurus' (hoard, treasury). The suffix "-y" is a Middle English noun-forming suffix from Old French '-ie', indicating a state, condition, or place.