A first cousin once removed is a cousin who is one generation away from being a first cousin. This means that they are either the child of ones first cousin or the first cousin of ones parent. For example, if your first cousin has a child, that child is your first cousin once removed. Another example is if your parent has a first cousin, that first cousin is your first cousin once removed. The term "removed" is used to indicate the generational difference between the two cousins.