What do you call the << operator in Ruby when it's used for appending stuff?

Question

In other contexts I know this << is called the bitshift operator. Is there a name for it when it's just used for append operations like you would do in an array or string (not sure what else you can append with it)?

I'd like to be able to use an English word to refer to it instead of saying "you know, the operator with the two left arrows that's not really the left bitshift operator".

Answer 1

Actually, I think append operator is the preferred term. This is what's used on p. 104 of The Ruby Programming Language.