What is "p major"

Shearwater \Shear"wa`ter\, n. [Shear + water; cf. G. wassersherer; -- so called from its running lightly along the surface of the water.] (Zo["o]l.) Any one of numerous species of long-winged oceanic birds of the genus Puffinus and related genera. They are allied to the petrels, but are larger. The Manx shearwater ( P. Anglorum), the dusky shearwater ( P. obscurus), and the greater shearwater ( P. major), are well-known species of the North Atlantic. See Hagdon.