Source : Webster's Revised Unabridged Dictionary (1913)

Pectoral \Pec"to*ral\, a. [L. pectoralis, fr. pectus, -oris the
   breast; cf. F. pectoral.]
   1. Of or pertaining to the breast, or chest; as, the pectoral
      muscles.

   2. Relating to, or good for, diseases of the chest or lungs;
      as, a pectoral remedy.

   3. (Zo["o]l.) Having the breast conspicuously colored; as,
      the pectoral sandpiper.

   {Pectoral arch}, or {Pectoral girdle} (Anat.), the two or
      more bony or cartilaginous pieces of the vertebrate
      skeleton to which the fore limbs are articulated; the
      shoulder girdle. In man it consists of two bones, the
      scapula and clavicle, on each side.

   {Pectorial cross} (Eccl.), a cross worn on the breast by
      bishops and abbots, and sometimes also by canons.

   {Pectorial} fins, or {Pectorials} (Zo["o]l.), fins situated
      on the sides, behind the gills. See Illust. under {Fin}.
      

   {Pectorial rail}. (Zo["o]l.) See {Land rail}
      (b) under {Land}.

   {Pectorial sandpiper} (Zo["o]l.), the jacksnipe
      (b) .

Source : WordNet®

pectoral arch
     n : the bony arch formed by the collarbones and shoulder blades
         in humans [syn: {shoulder girdle}]