• (n.) A muscle which serves to retain an organ or part in place, esp. when retracted. See Illust. of Phylactolemata.
<anatomy, zoology> A muscle which serves to retain an organ or part in place, especially. When retracted. ... Origin: L, a retainer. ... (10 Mar 1998) ... 
Re·ten'tor noun [ Latin , a retainer.] (Zoology) A muscle which serves to retain an organ or part in place, esp. when retracted. See Illust. of Phylactolemata .