Dictionary.com
Thesaurus.com

definiens

American  
[dih-fin-ee-uhnz] / dɪˈfɪn i ənz /

noun

plural

definientia
  1. something that defines, especially the defining part of a dictionary entry.

  2. Logic. an expression in terms of which another may be adequately defined.


definiens British  
/ dɪˈfɪnɪənz /

noun

  1. the word or words used to define or give an account of the meaning of another word, as in a dictionary entry Compare definiendum

"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 definiens

1870–75; < Latin dēfīniēns, present participle of dēfīnīre; see define