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complementizer

American  
[kom-pluh-muhn-tahy-zer] / ˈkɒm plə mənˌtaɪ zər /

noun

Linguistics.
  1. an element or elements marking a complement clause, as that in We thought that you forgot, for … to in For you to go all the way there would be silly, or possessive … -ing in Barbara's leaving so early worried them.


complementizer British  
/ ˈkɒmplɪmənˌtaɪzə /

noun

  1. generative grammar a word or morpheme that serves to introduce a complement clause or a reduced form of such a clause, as that in I wish that he would leave

"Collins English Dictionary — Complete & Unabridged" 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Etymology

Origin of complementizer

complement + -ize + -er 1