Nutrition (Lat. nutrio, to nourish). The processes by which the nourishment of the body is accomplished.
Odontoid (Gr. ὀδούς, a tooth, εἶδσ, shape). The name of the bony peg of the second vertebra, around which the first turns.
Œsophagus. Literally, that which carries food. The tube leading from the throat to the stomach; the gullet.
Olecranon (Gr. ὠλένη, the elbow, and κρανίον, the top of the head). A curved eminence at the upper and back part of the ulna.
Olfactory (Lat. olfacio, to smell). Pertaining to the sense of smell.
Optic (Gr. ὀπτεύω, to see). Pertaining to the sense of sight.
Orbit (Lat. orbis, a circle). The bony socket or cavity in which the eyeball is situated.
Organ (Lat. organum, an instrument or implement). A portion of the body having some special function or duty.
Osmosis (Gr. ὠσμός, impulsion). Diffusion of liquids through membranes.
Ossa Innominata, pl. of Os Innominatum (Lat.). “Unnamed bones.” The irregular bones of the pelvis, unnamed on account of their non-resemblance to any known object.