Posted by ESC on July 22, 2000
Irish twins. Today I heard this term used during a "book talk" on TV by Charles Osgood, radio guy and author of "See You on the Radio." Mr. Osgood said he and his sister were not twins but they were born in the same year - one in January and the other the following December. So they were called "Irish twins."
And while I'm on the subject, there is a name for people who not twins, triplets etc. They are called "singletons."