In the direct line, as many degrees are counted as there are generations between the persons: thus, the child is, with regard to the father and mother, in the first degree, the grandson or granddaughter in the second; and conversely the father and mother with regard to the child and the forefathers with regard to the grandson or granddaughter; and so on.
In collateral lines, the degrees are counted by generation, from one of the parents up to and not including the common author, and from the latter to the other parent.
Thus, brothers and sisters are in the second degree; uncle or aunt and nephew or niece are in the third degree; first cousins in the fourth; so on.