Please explain how first, second, third and so on cousins work?

Question

Also what does ‘once and twice removed’ cousins work in that context?

In: 14

Answer 1

It comes down to how close is the closest common ancestor. For first cousins the closest common ancestor was a grandparent, for second cousins it is a great-grandparent, etc. If there is a generational difference, you use the closer connection. Example: if Alice’s grandparents were also Bobs great-grandparents, they would be first cousins.

The ‘removed’ part is where the generation separation comes in. In the above example, Alice and Bob are different generations from their common ancestor (grandparents vs great-grandparents), so they would be first cousins once removed.