What Do “Second Cousin” and “Cousin Once Removed” Mean?

“Second Cousin” and“Cousin Once Removed” are genealogy terms used to describe kinship which are frequently misunderstood.  They are often wrongly used interchangeably when, in reality, they are describing completely different relationships.

The precise relationship between yourself and your cousin is determined by the common ancestor you share (which specifies the degree such as“First”, “Second” and “Third”) and the generation gap between yourself and your cousin (which specifies the separation “Once Removed”, “Twice Removed” and “Three Times Removed”).

Your “First Cousin” is a relative to whom you are linked via one, or both, of your grandparents (for example a child of one of your uncles or aunts).

Your “Second Cousin” is a relative to whom you are linked via one, or both, of your great-grandparents.

Your “Third Cousin” is a relative to whom you are linked via one, or both, of your great-great-grandparents.

The removal modifier (“Once Removed”, “Twice Removed” etc.) can then be added to the above terms to specify the generation gap between your cousin and yourself.  Note that the ages of your cousin and yourself are irrelevant… it is the generation gap which is important.

“Once Removed” means that there is a generation gap of one generation between your cousin and yourself.  A “First Cousin Once Removed” is therefore the grandchild of one of your uncles or aunts.

“Twice Removed” means that there is a generation gap of two generations between your cousin and yourself.  A “First Cousin Twice Removed” is therefore a great-grandchild of one of your uncles or aunts.

“Three Times Removed” means that there is a generation gap of three generations between your cousin and yourself.  A “First Cousin Three Times Removed” is therefore a great-great-grandchild of one of your uncles or aunts.

Note that the removal modifier can signify a generation gap upwards or downwards.

If you are mathematically inclined then you may find it easier to determine the degree and separation modifiers by counting generations:  The first step is to determine the ancestor which your cousin and yourself share. You then count the number of generations you need to climb up your Family Tree to reach this common ancestor and deduct one from the result.  The answer is the degree.  If therefore you need to climb 3 generations to reach your common ancestor then your cousin is a “Second Cousin”. The next step is to count the generations you need to travel from this common ancestor to your cousin and deduct from this the number of generations from yourself to your common cousin.  If therefore you had to climb 3 generations to your common ancestor and then descend 4 generations to reach your cousin that would make them your “Second Cousin Once Removed” (3 – 1 = Second Cousin, 3 – 4 = Once Removed).

Hopefully, after reading all the above explanations you can now see that “Second Cousin” and “Cousin Once Removed” describe completely different kinship: Your “Second Cousin” is a cousin linked to you via one, or both, of your great-grandparents whereas your “Cousin Once Removed” is a grandchild of one of your aunts or uncles (who are linked to you via your grandparents).