1. [n]  an equating verb (such as `be' or `become') that links the subject with the complement of a sentence
2. [adj]  (grammar) syntactically connecting sentences or elements of a sentence; "`and' is a copulative conjunction"

COPULATIVE is a 10 letter word that starts with C.

1. \Cop"u*la"tive\, a. [L. copulativus: cf. F.
   copulatif.]
   Serving to couple, unite, or connect; as, a copulative
   conjunction like ``and''.
   
   

2. \Cop"u*la*tive\, n.
   1. Connection. [Obs.] --Rycaut.
   
   2. (Gram.) A copulative conjunction.