Definition of "specifier"

specifier

/ˈspɛsəˌfaɪɚ/

noun
plural specifiers
1. A person or thing that specifies.
  Quotations
  The specifiers of the Freightliner network had the foresight to base the rail journey on carrying ISO containers which are 8ft wide and originally 8ft tall (although now increased to a height of 9ft 6ins), with a variety of lengths.
  2020 May 20, Industry Insider, “An online boost for freight”, in Rail, page 68
2. (linguistics) A component of a phrase that is non-recursive and not found as a sister of the head of the phrase, but rather as a daughter of the maximal projection of the phrase.