Skew group
Beginner
A set of memory cells that must all get the clock at about the same time.
Novice
A set of clock sinks that CTS must deliver the clock to at about the same time. Sinks in different groups don’t need to be matched with each other.
Expert
Skew groups tell CTS which sinks actually exchange data: they separate unrelated clock domains, leave out test-only flip-flops, balance across generated clocks, and give memory blocks or I/O flip-flops their own latency targets.