NOTE: refers to a physical boundary, not a psychological/abstract one. (Sense 2)
A herd of deer stood at the water's edge.
They built a wooden railing around the edge of their deck.
The armies gathered on the edge of a great plain.
During the talk, I wrote notes on the edge of the handout.
The hang glider kicked off the edge of the cliff.
The new action thriller kept audiences on the edge of their seat. (figurative extension)
Is there an edge to the universe, or does it curve back on itself?
WordNet 3.0 Sense Numbers: 1, 2
NOTE: usually has a negative connotation, most often in the phrase 'on edge'.
NOTE: X is in a state of 'edge' - about to transition to some other situation.
His brother is on the edge of a nervous breakdown.
The economy was teetering on the edge of a recession.
They are thrill seekers who like to live on the edge.
The sound of distant bombing kept us on edge all night.
The markets are on edge because of the uncertainty of this crisis.
WordNet 0.0 Sense Numbers: 2c
NOTE: implies 'edge' is the sharp side of an object.
Bill nicked himself with the edge of the razor.
This chef's knife has a good edge on it for chopping and slicing.
She was involved in the leading edge of several 20th-century art movements. (metaphoric)
The edge of the legislature has been blunted pretty effectively. (metaphoric usage)
They are working on the cutting edge of cancer research. (metaphoric usage)
WordNet 3.0 Sense Numbers: 3
NOTE: does not refer to the structural side of an object (Sense 3)
NOTE: implies X has a trait or attribute Y (Y is 'edge')
His editorials have a satirical edge to them.
They perform rock music with a bluesy edge.
She was still smiling, but there was an edge to her voice.
The chocolate brownies took the edge off our appetite.
Voters didn't like the candidate's hard edge.
WordNet 3.0 Sense Numbers: 4
NOTE: implies X enjoys an advantageous relationship (= edge) to Y, who is at a disadvantage somehow.
Her summers at math camp gave her an edge on the advanced placement exams.
They've lost their competitive edge in the manufacturing sector.
The pitching talent of that ball club has really given them an edge this year.
By the 1980s the Japanese had gained a decisive edge in the memory chip market.
WordNet 3.0 Sense Numbers: 5