sŭb-ĕdo, ēdi, 3, v. a.,
to eat , waste , or wear away below : e scopulo, quem rauca subederat unda, Ov. M. 11, 783; Hier. in Jer. 1, 2, 37.
sub-edō ēdī, —, ere, to eat away below, wear away: scopulus, quā subederat unda, O. ...
An Elementary Latin Dictionary