To expand; distend; spread out; enlarge or extend in all directions: as, air dilates the lungs; to dilate the pupil of the eye.To set forth at length; relate at large; relute or describe with full particulars; enlarge upon.Synonyms To swell, spread out, amplify.To spread out; expand; distend; swell; enlarge.To speak at length; dwell on particulars; enlarge; expatiate; descant: used absolutely or with upon or on.Broad; extended.