Yours, Etc.: Origins and Uses of 8 Sign-Offs
late 14c., from Old French dilater, from Late Latin dilatare "make wider, enlarge," from dis- "apart" (see dis-) + latus "wide" (see latitude). Related: Dilated; dilating.
dilate di·late (dī-lāt', dī'lāt')v. di·lat·ed, di·lat·ing, di·lates To make or become wider or larger.