nostrilandia on Nostr: "The number associated with your cousin has to do with how many generations away your ...

"The number associated with your cousin has to do with how many generations away your common ancestor is. For example:

First cousins share a grandparent (2 generations)
Second cousins share a great-grandparent (3 generations)
Third cousins share a great-great-grandparent(4 generations)
Fourth cousins share a 3rd-great grandparent (5 generations)"

The link also explains the once removed thing. Which is basically the difference if the generations back to the common ancestor are different. Bob's relationship to a child of Alice would be 2nd cousins once removed since Alice's child is one more generation away (3 hops) from the common ancestor than Bob (only 2 hops).

https://www.familysearch.org/en/blog/cousin-chart