pec·to·ral / ˈpektərəl/ • adj. of or relating to the breast or chest: pectoral development. ∎  worn on the chest: a pectoral shield.• n. (usu. pectorals) a pectoral muscle. ∎  a pectoral fin. ∎  an ornamental breastplate, esp. one worn by a Jewish high priest.

pectoral (pek-ter-ăl) adj. relating to the chest or breast. p. girdle see shoulder girdle. p. muscles the chest muscles: the pectoralis major, which draws the arm forward across the chest, and the pectoralis minor, which depresses the shoulder.

pectoral pert. to the breast or chest XVI; sb. object worn on the breast XV; medicine for affections of the chest XVII. — (O)F. — L. pectorālis, f. pectus, -tor- breast, chest.