Otoconia (Gr. οὖς, an ear, and κονία, dust). Minute crystals of lime in the vestibule of the ear; also known as otoliths.
Palate (Lat. palatum, the palate). The roof of the mouth, consisting of the hard and soft palate.
Palpitation (Lat. palpitatio, a frequent or throbbing motion). A violent and irregular beating of the heart.
Papilla. The small elevations found on the skin and mucous membranes.
Paralysis (Gr. παραλύω, to loosen; also, to disable). Loss of function, especially of motion or feeling. Palsy.
Parasite. A plant or animal that grows or lives on another.
Pelvis. Literally, a basin. The bony cavity at the lower part of the trunk.
Pepsin (Gr. πέπτω, to digest). The active principle of the gastric juice.
Pericardium (Gr. περί, about, and καρδία, heart). The sac enclosing the heart.
Periosteum (Gr. περί, around, ὀστέον, a bone). A delicate fibrous membrane which invests the bones.