The Collaborative International Dictionary of English v.0.48:
Macroglossia \Mac`ro*glos"si*a\, n. [NL. See Macro-, and Glossa.] (Med.) Enlargement or hypertrophy of the tongue. [1913 Webster]WordNet (r) 3.0 (2006):
macroglossia n 1: a congenital disorder characterized by an abnormally large tongue; often seen in cases of Down's syndrome