JEDEC – The magnitude of the difference in propagation delay times between two inputs and a single output of an integrated circuit at identical operating conditions.

TI – The difference between any two propagation delay times that originate at different inputs and terminate at a single output. Input skew describes the ability of a device to manipulate (stretch, shrink, or chop) a clock signal. Typically, this is accomplished with a multiple-input gate wherein one of the inputs acts as a controlling signal to pass the clock through. tsk(i) describes the ability of the gate to shape the pulse to the same duration, regardless of the input used as the controlling input.