Concha \Con"cha\, n. [LL. (in sense 1), fr. ? concha. See Conch.]

1. (Arch.) The plain semidome of an apse; sometimes used for the entire apse.

2. (Anat.) The external ear; esp. the largest and deepest concavity of the external ear, surrounding the entrance to the auditory canal.

Source: Webster's Revised Unabridged Dictionary (1913)