Demersion

n. [ Cf. F. émersion. See Emerge. ] 1. The act of emerging, or of rising out of anything; as, emersion from the sea; emersion from obscurity or difficulties. [ 1913 Webster ]

Their immersion into water and their emersion out of the same. Knatchbull. [ 1913 Webster ]

2. (Astron.) The reappearance of a heavenly body after an eclipse or occultation; as, the emersion of the moon from the shadow of the earth; the emersion of a star from behind the moon. [ 1913 Webster ]