Pectoral: referring to the shoulder region. see also girdle.

Pectoral fin: paired fins on either side of the body, usually near or just behind the gill opening; these correspond to the arm or foreleg of terrestrial vertebrates.

Pectoral flap: a scaly elongate flap on the axil of the pectoral fin.

Pectoral lobe: ?? (figure typical fish).

Alternative forms for pectoral : pectoral fin, pectoral flap, pectoral lobe.