The Collaborative International Dictionary
Laxator
Laxator \Lax*a"tor\, n. [NL., fr. L. laxare, laxatum, to loosen.] (Anat.) That which loosens; -- esp., a muscle which by its contraction loosens some part.
Wiktionary
laxator
n. (context anatomy English) A muscle whose contraction loosens some part.