1. An abbreviation for the Latin prepositional phrase sub verbo ('under the word') or sub voce (literally, 'under the voice'), indicating that something is to be found under a particular heading in a reference book. S.v. is typically used in lieu of page references in citing dictionaries and similar works, since it is easy enough to look up an entry in an alphabetized list without knowing what page it's on. Furthermore, since pagination may change from one edition of a work to the next, or even disappear altogether when a work is converted into electronic form, an s.v. citation is frequently stabler than a page reference.

    Example: "The OED, s.v. index, states that the Catholic Index librorum prohibitorum was published under Pius IV."
  2. See supplementary vote.