A more thorough explanation:

Definition: A cater cousin is a distant relative, typically a cousin in the fourth degree. The term comes from the French word "quatrecousin."

• My cater cousin, who I've only met once at a family reunion, just added me on Facebook.
• Although we're not close, I still send a Christmas card to my cater cousin every year.

These examples illustrate how a cater cousin is someone who is related to you, but not closely. They may be someone you've only met a few times or someone you don't have a strong relationship with. The term "cater cousin" is used to distinguish these distant relatives from those who are closer, such as first or second cousins.