What does the triangle on the clock input of a j-k flip-flop mean?

The triangle on the clock input of a J-K flip-flop signifies that the flip-flop is edge-triggered, meaning it responds to changes in the clock signal at specific edges, typically the rising edge (transition from low to high). This edge-triggering allows the flip-flop to capture and change its output state based on the inputs (J and K) only at that precise moment, providing improved timing control in digital circuits.