I’m going to the christening of my cousin’s first son soon. What is the proper name for his relation to me?

Second nephew? Nephew once removed? Nothing?

Looking at the overall picture, what's the accepted rule for the naming of all of our various relations?

  • 1
    Also, no idea what tags to use - suggestion received with interest! – Jon Hadley Aug 21 '10 at 19:15
  • Does this one look ok? – GSerg Aug 21 '10 at 19:19
  • I believe the phrase you all are looking for is kinship terms (en.wikipedia.org/wiki/Kinship_terminology) – Kosmonaut Aug 21 '10 at 20:13
  • If you think it is confusing in English, in Japanese (and I think Chinese) there are different names for people related to through your mother and father. – JohnFx Aug 21 '10 at 21:25
  • And if they are older or younger than you makes a difference. They do this in Korean too. – Kosmonaut Aug 21 '10 at 23:38

Kinship chart

Your cousin's first son is your first cousin once removed. It is quite confusing!

  • 6
    +1 Nice graph, Kosmonaut! One question, what do the numbers represent? – JohnFx Aug 21 '10 at 21:24
  • 3
    I am pretty sure that they are the degree of relationship. So your son or daughter is 50% of your genes, grandfather is 25% of your genes, and so on. First cousins share 6.25%. Oh, and this came from Wikipedia (I didn't go and make this awesome graph just for this answer :) – Kosmonaut Aug 21 '10 at 23:36
  • 2
    I am familiar with this graphic, and yes, the number is the percentage of shared genes. – Chris Noe Aug 21 '10 at 23:50
  • 1
    So, combining this with @MrShiny's answer: if I understand correctly, all the 'cousin' relationships are bi-directional/symmetrical? – Benjol Dec 8 '10 at 5:48
  • 2
    It's not quite the percentage of your genes that they share: a grapefruit will share many of your genes, and any other human will share the vast majority of your genes. It's roughly the percentage of those genes that you have, that are very rare in your community, that they share. Assuming that none of your relatives were related their partners other even distantly, which is unlikely. – bdsl Aug 11 '11 at 19:05

It's very easy to determine the relationship in English.

First, find your common ancestor. Siblings have the same father, cousins have the same grandfather, etc.

  • Same grandfather means First cousin.
  • Same great-grandfather means second cousin.
  • Same great-great-grandfather means third cousin.

If you are not in the same generation, pick the shortest one, then the generation distance is how many times removed.

  • Your cousin's child is your first cousin, once-removed.
  • That person's child is your first cousin, twice removed.

The labels work the same in both directions so "first cousin, once removed" identifies the relationship to the speaker irrespective of whether that person is in the younger generation or not.


My brother is into genealogy, and he described for me a simple way to remember these relationships.

  1. Going up-generation uses ordinals. So your cousin is your first cousin. Your parent's cousins are your second cousins. Your grandparent's cousins are your third cousins.

  2. Going down-generation use removes. So your first cousin's child is your first cousin once-removed. Your third cousin's grandchild is your third cousin twice-removed.

This contradicts Mr. Shiny's answer though, because the relationships are not symmetrical. To my second cousin (my father's cousin), I am a first cousin once-removed.


Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.