Is it OK to date second cousin?

In the United States, second cousins are legally allowed to marry in every state. However, marriage between first cousins is legal in only about half of the American states.

What does a 4th cousin mean?

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) Third cousins share a great-great-grandparent (4 generations) Fourth cousins share a 3rd-great grandparent (5 generations)