Hold time
Beginner
How long the data must stay unchanged after the clock tick so the memory cell isn’t confused.
Novice
The minimum time data must stay steady after the capturing tick. If new data races in too soon, it overwrites the value being captured. The hold check: launch arrival + data delay must be no earlier than capture arrival + hold time. The clock period does not appear in it.
Expert
The hold check pairs the fastest (early) data with the latest capture clock. Because the clock frequency does not appear in it, a hold failure in silicon breaks the chip at any speed. Most hold-fixing delay cells are added right after CTS, once real skew is known.