Is there a technical term for a function that takes one argument and returns an object of the same type?

I'm co开发者_运维技巧nsidering functions of one argument of type T that return an argument of type T. I seem to vaguely recall that there is a name for that sort of function, maybe homo-something. Is there such a term?

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After an hour-long wiki-crawl, it appears that an appropriate term would be "endofunction".

http://en.wikipedia.org/wiki/Endomorphism#Endofunctions_in_mathematics