"a person who shares the same date of birth"
My son and his nephew share the same date of birth, and we are looking for the term in Spanish which encompasses that relationship: a shared birthday.
13 Answers
Why not coin a new term? Like, maybe, birthday buddies. Compinches de cumpleaños?
Hmmm, cumpleaños común?? Sonds weird... 
I'm almost sure that there is not a Spanish word for this condition.
ok i when the person is the same birth we say is spanish (mi hijo y su sobrino cumplen años el mismo dia.i know spanish and when is like that i say mi hermano y mi primo cumplen años el mismo dia i go tell you what you wanna say in spanish maybe this help you figure out (Mi hijo y su sobrino comparten la misma fecha de nacimiento, y estamos buscando el término en español que abarca esa relación: un cumpleaños compartido)
My sister and her daughter share the same birthday. I am sure that there is not a word in English for this. Because in 40+ years I am sure I would have heard it.
At least in Mexico, when one is born on a certain day, it may determine what his or her name will be. For instance, if one is born on December 8th, his name may be "Conception" because the 8th of December is the Day of the Immaculate Conception. In Mexico, they use the word "tocayo" for those who have the same name. But sometimes also for the same birthday.
I don't believe there is a single word in either Spanish or English for this. It's not like, ie: Namesake......Tocayo
does such a word exist in english??
I would say: "they share a birthday" or "they have the same birthday"
A simple question - if my postman was born on the same day of the same month does he share a birthday with me? He's three years younger so we weren't born on the same day.
...and how does this affect the original question. Is it about a common "fecha de nacimiento" or about a common "cumpleanos", two different concepts.
It's quite unusual for a person and his nephew to share the same date of birth (to have been born on the same day), usually they would belong to different generations (although they might share the same birthday [the day on which they celebrate their births]).
In either event, there's no short-cut way to say this in English and (as already pointed out) there isn't in Spanish either.
I just asked my Spanish girlfriend and she informed me that no such word exists.
I think she is asking for a single word to name this condition. That does not exist. You can say "cumplen años el mismo día", but I don't think this is the answer she's looking for.
I'm not Catholic so I don't understand the details, but wouldn't they share the same Saint's day? Then there's astrology...
