English to English

noun (n)

• two words that can be interchanged in a context are said to be synonymous relative to that context(noun.communication)

  Synonym:
  equivalent word
  Antonym:
  antonym, opposite, opposite word
  

  source: wordnet30
• One of two or more words (commonly words of the same language) which are equivalents of each other; one of two or more words which have very nearly the same signification, and therefore may often be used interchangeably. See under Synonymous.(noun)

  source: webster1913
• An incorrect or incorrectly applied scientific name, as a new name applied to a species or genus already properly named, or a specific name preoccupied by that of another species of the same genus; -- so used in the system of nomenclature (which see) in which the correct scientific names of certain natural groups (usually genera, species, and subspecies) are regarded as determined by priority.(noun)

  source: webster1913