The Collaborative International Dictionary of English v.0.48:

V \V\ (v[=e]).
   1. V, the twenty-second letter of the English alphabet, is a
      vocal consonant. V and U are only varieties of the same
      character, U being the cursive form, while V is better
      adapted for engraving, as in stone. The two letters were
      formerly used indiscriminately, and till a comparatively
      recent date words containing them were often classed
      together in dictionaries and other books of reference (see
      U). The letter V is from the Latin alphabet, where it
      was used both as a consonant (about like English w) and as
      a vowel. The Latin derives it from a form (V) of the Greek
      vowel [Upsilon] (see Y), this Greek letter being either
      from the same Semitic letter as the digamma F (see F),
      or else added by the Greeks to the alphabet which they
      took from the Semitic. Etymologically v is most nearly
      related to u, w, f, b, p; as in vine, wine; avoirdupois,
      habit, have; safe, save; trover, troubadour, trope. See U,
      F, etc.
      [1913 Webster] See Guide to Pronunciation, [sect] 265;
      also [sect][sect] 155, 169, 178-179, etc.
      [1913 Webster]

   2. As a numeral, V stands for five, in English and Latin.
      [1913 Webster]

WordNet (r) 3.0 (2006):

v
    adj 1: being one more than four [syn: five, 5, v]
    n 1: a unit of potential equal to the potential difference
         between two points on a conductor carrying a current of 1
         ampere when the power dissipated between the two points is
         1 watt; equivalent to the potential difference across a
         resistance of 1 ohm when 1 ampere of current flows through
         it [syn: volt, V]
    2: a soft silvery white toxic metallic element used in steel
       alloys; it occurs in several complex minerals including
       carnotite and vanadinite [syn: vanadium, V, atomic
       number 23]
    3: the cardinal number that is the sum of four and one [syn:
       five, 5, V, cinque, quint, quintet, fivesome,
       quintuplet, pentad, fin, Phoebe, Little Phoebe]
    4: the 22nd letter of the Roman alphabet [syn: V, v]

The Free On-line Dictionary of Computing (30 December 2018):

V

   Upper case V, ASCII character 86, known in INTERCAL as
   book.

   1. A testbed for distributed system research.

   2. Wide-spectrum language used in the knowledge-based
   environment CHI.  "Research on Knowledge-Based Software
   Environments at Kestrel Inst", D.R.  Smith et al, IEEE Trans
   Soft Eng SE-11(11):1278-1295 (1985).