Second cousins are the children of your parent's first cousins. This means that you share a common great-grandparent with your second cousins, but not a grandparent. For example, if your mother has a cousin, that cousin's children are your second cousins. In terms of family trees, second cousins are part of the extended family. They are one generation further away than first cousins, who share a grandparent. While second cousins may not see each other as often as first cousins, they can still have a familial bond and share similar family histories through their common ancestors.