The Collaborative International Dictionary of English v.0.48:
Cacuminal \Ca*cu"mi*nal\, a. [L. cacumen, cacuminis, the top, point.] (Philol.) Pertaining to the top of the palate; cerebral; -- applied to certain consonants; as, cacuminal (or cerebral) letters. [1913 Webster]WordNet (r) 3.0 (2006):
cacuminal adj 1: pronounced with the tip of the tongue turned back toward the hard palate [syn: cacuminal, retroflex]