- vacant[vacant 词源字典]
- vacant:  Latin vacāre meant ‘be empty’. Its present participle vacāns has provided English with vacant, while its past participle lies behind English vacate  and vacation . It also formed the basis of an adjective vacuus ‘empty’, from which English gets vacuous  and vacuum  (the term vacuum cleaner is first recorded in 1903, and the consequent verb vacuum in 1922). English avoid and void come from a variant of Latin vacāre.
=> vacate, vacuum[vacant etymology, vacant origin, 英语词源]
- vaccine:  Vaccine was adapted from Latin vaccīnus, which means literally ‘of a cow’ (it was a derivative of vacca ‘cow’, source of French vache). It was used by the British physician Edward Jenner at the end of the 18th century in the terms vaccine disease for ‘cowpox’, and hence vaccine inoculation for the technique he developed of preventing smallpox by injecting people with cowpox virus. The verb vaccinate was coined from it at the beginning of the 19th century, but vaccine itself was not used as a noun, meaning ‘inoculated material’, until the 1840s.
- vagabond:  A vagabond is etymologically a ‘wanderer’. The word comes via Old French vagabond from Latin vagābundus, which was derived from vagārī ‘wander’ (source also of English termagant, vagary , and vagrant ). And vagārī in turn was based on vagus ‘wandering, undecided’ (source also of English vague ).
=> termagant, vagary, vagrant, vague
- vagina: see vanilla
- vain:  Latin vānus meant ‘empty’ (it was related to vacuus ‘empty’, source of English vacuum). It passed into English via Old French vain in the sense ‘worthless’, and the main modern meaning ‘conceited’ did not develop until the 17th century. Also from vānus come English evanescent, vanish, vanity , and vaunt , and wane, want, etc go back to the same ultimate Indo-European base.
=> evanescent, vanish, vanity, vaunt, wane, want
- vainglorious: see glory
- vale: see valley
- valency: see value
- valet: see varlet
- valiant: see value
- valid:  Something that is valid is etymologically ‘strong’, and hence ‘effective’. The word comes via French valide from Latin validus ‘strong, effective’, which was derived from the verb valēre ‘be strong’ (source also of English valiant, valour, value, etc). The negative form invalid  also goes back to Latin, but its specific application to infirm people, differentiated with a distinct pronunciation, was introduced from French in the 17th century.
=> valiant, valour, value
- valley:  Valley comes via Anglo-Norman valey from *vallāta, a Vulgar Latin derivative of Latin vallis ‘valley’, whose origins are uncertain. A more direct English descendant of vallis is vale .
- value:  To have value is etymologically to be ‘strong’ or ‘effective’, and hence to have ‘worth’. The word was borrowed from Old French value, a noun use of the feminine past participle of valoir ‘be worth’. This was descended from Latin valēre ‘be strong, be of value’, which also produced English avail , available  (which originally meant ‘advantageous’, and was not used for ‘accessible for use’ until as recently as the 19th century), convalesce , valency , valiant , valid, and valour .
=> available, convalesce, valency, valiant, valid, valour
- valve:  The etymological notion underlying valve is of a door opening and closing. The word was adapted from Latin valva, which denoted one of the sections of a folding or revolving door, and may have had links with volvere ‘roll’ (source of English revolve). It carried its original meaning with it into English, but it was not used at all widely until various metaphorical senses, such as ‘flap controlling the flow of a fluid’ and ‘half of a shell’, evolved. The electronic valve is so called because current can flow in only one direction through it; the usage dates from the early 20th century.
- vamp: English has two distinct words vamp. The now dated slang term for a ‘seductive woman’  is short for vampire. The other vamp, ‘extemporize on the piano’, was originally a noun meaning the ‘part of a stocking that covers the foot and ankle’ . It was borrowed from Anglo-Norman *vaumpé, a reduced form of Old French avantpié. This was a compound noun formed from avant ‘in front’ and pié ‘foot’. From it in the 16th century was derived a verb vamp, meaning ‘provide a stocking with a new vamp’, and this evolved semantically via ‘patch up, repair’ to, in the 18th century, ‘extemporize’.
=> vampire; foot, pedal
- vampire:  Vampire probably goes back ultimately to ubyr, a word for ‘witch’ in the Kazan Tatar language of an area to the east of Moscow. This was borrowed into Russian as upyr’, and from there probably found its way into Hungarian as vampir. English acquired it via French vampire or German vampir. The application of the word to a type of bloodsucking bat was introduced by the 18th-century French biologist Buffon.
- van: see caravan
- vandal:  The term vandal commemorates a Germanic tribe, the Vandals, who sacked Rome in 455 AD, and thereby earned themselves a reputation as destroyers of civilization. Their name for themselves was *Wandal-, which etymologically means ‘wanderer’.
- vane:  Vane is an alteration of an earlier fane ‘flag, weather-cock’, which was descended from Old English fana. This in turn came from a prehistoric Germanic *fanon. The change from fane to vane took place in southwest England, where initial f and s have a tendency to become v and z (as in zyder for cyder).
- vanguard:  Vanguards have nothing to do with guarding vans. The word denotes etymologically an ‘advance guard’. It is short for the long defunct avantgard, which was borrowed from Old French avant-garde, a compound formed from avant ‘in front’ and garde ‘guard’. (Its modern French descendant was reborrowed into English as avant-garde .)
=> avant-garde, guard