Having a sharp border or margin, or having moved gradually in a particular direction.
From Old English 'ecg' meaning sharp side of a blade, related to 'egg' (to incite). The sense of 'moving gradually' developed from the idea of moving along an edge or border.
The phrase 'cutting edge' literally refers to the working part of a blade, but metaphorically captures how innovation happens at the boundary between the known and unknown - always at the edge of possibility.
Complete word intelligence in one call. Free tier — 50 lookups/day.