Apertu´ra, n. An opening; as, apertura auris, ear-opening.

A´pex, n.; pl. apices. Tip or point of anything.

Apohy´al, a. A portion of the “horn” of the hyoid bone.

Aponeuro´sis, n. Broad, strong, fibrous membrane or band; fascia.

Apoph´ysis, n. Any natural bony prominence of notable size.

Apposed´, a. Mutually fitted, adapted; set over against; meeting closely and exactly. The tomia of the bill are usually apposed.

Apte´rium, n.; pl. apteria. Tract of skin where no feathers grow. Compare Pteryla.

Aquat´ic, a. Pertaining to the water; said of birds frequenting water, and thence drawing subsistence.

A´queous, a. Watery. Said of the fluid in the anterior chamber of the eye. See Vitreous.

Aq´uiline, a. Eagle-like; belonging to the Aquilinæ.