"practiced, conversant, acquainted," c. 1600, from past participle of obsolete verse "to turn over" (a book, subject, etc.) in study or investigation, from French verser "to turn, revolve" as in meditation (12c.), from Latin versare "be employed, busy oneself," literally "to turn to, turn often; think over," frequentative of vertere "to turn" (from PIE root *wer- (2) "to turn, bend").
late 15c., "to use to one's profit, to increase (income)," from Anglo-French emprouwer "to turn to profit" (late 13c.), from Old French en-, a causative prefix or from em-, + prou "profit," from Latin prode "advantageous" (see proud (adj.)).
Spelling with -v- was rare before 17c.; it apparently arose from confusion of -v- and -u-. Spelling otherwise deformed by influence of words in -prove. Meaning "make better, raise to a better quality or condition" first recorded 1610s. Intransitive sense "get better" is from 1727. Phrase improve the occasion retains the etymological sense. Meaning "to turn land to profit" (by clearing it, erecting buildings, etc.) was in Anglo-French (13c.) and survived or was revived in the American colonies and Australia. Hence, "make good use of, occupy (a place) and convert to some purpose."
"jump or leap over," especially by aid of the hands or a pole, 1530s, transitive (implied in vaulting); 1560s, intransitive, from French volter "to gambol, leap," from Italian voltare "to turn," from Vulgar Latin *volvitare "to turn, leap," frequentative of Latin volvere "to turn, turn around, roll" (from PIE root *wel- (3) "to turn, revolve"). Related: Vaulted; vaulting.
c. 1300, "a change or turn from one religion to another," especially to Christianity, from Old French convertir "to turn around, turn towards; change, transform; convert, win over," from Vulgar Latin *convertire, from Latin convertere "turn around, transform," from assimilated form of com "with, together" (see con-) + vertere "to turn" (from PIE root *wer- (2) "to turn, bend").
The Latin verb was glossed in Old English by gecyrren, from cierran "to turn, return." General sense of "change into another form or substance, transmute" is from late 14c. Transitive sense of "turn from one use or destination to another" is from late 15c. Related: Converted; converting.