Treasure
Middle English: from Old French tresor, based on Greek thēsauros (see thesaurus).
wiktionary
From Middle English tresour, from Old French tresor(“treasury”), from Latin thēsaurus(“treasure”), from Ancient Greek θησαυρός(thēsaurós, “treasure house”). Displaced native Middle English schat. Doublet of thesaurus.
etymonline
treasure (n.)
mid-12c., tresor, from Old French tresor "treasury, hoard, treasure" (11c., Modern French trésor), from Gallo-Roman *tresaurus, from Latin thesaurus "treasury, treasure" (source also of Spanish, Italian tesoro), from Greek thēsauros "store, treasure, treasure house," related to tithenai "to put, to place," from reduplicated form of PIE root *dhe- "to set, put." In Middle English also thresur, etc.; modern spelling is from 16c. Replaced Old English goldhord, maðm. General sense of "anything valued" is recorded from c. 1200. Treasure hunt is first recorded 1913. For treasure trove, see trove.
treasure (v.)
late 14c., "to amass treasure; to store up for the future," also figurative, "regard as precious, retain carefully in the mind," from treasure (n.). Related: Treasured; treasuring.
