Vein
Middle English: from Old French veine, from Latin vena . The earliest senses were ‘blood vessel’ and ‘small natural underground channel of water’.
wiktionary
From Middle English veyne, borrowed from Anglo-Norman veine, from Latin vēna(“a blood-vessel; vein; artery”) of uncertain origin. See vēna for more. Displaced native edre, from ǣdre (whence edder).
etymonline
vein (n.)
c. 1300, from Old French veine "vein, artery, pulse" (12c.), from Latin vena "a blood vessel," also "a water course, a vein of metal, a person's natural ability or interest," of unknown origin. The mining sense is attested in English from late 14c. (Greek phleps "vein" had the same secondary sense). Figurative sense of "strain or intermixture" (of some quality) is recorded from 1560s; that of "a humor or mood, natural tendency" is first recorded 1570s.
