Gate capacitance
Beginner
How much electric charge a transistor’s gate must be filled with before the switch flips. More charge takes more time and energy.
Novice
The capacitance between the gate and the channel, about . Every time a signal changes, the circuit driving it must charge or discharge the gates it connects to.
Expert
plus overlap and fringe terms, typically 1–2 fF per µm of width. It dominates the input load of a logic gate and, with on-resistance, sets the RC delay unit for the whole technology.