Word drop: have a beer or two

Question

What is it called when a word is dropped (or implied): "Have a beer or two" == "Have a beer or two beers"

Does this phenomenon have a name? Any pointers on where to learn more about it are appreciated.

Answer 1

This would be Noun ellipsis or N-ellipsis:

... a mechanism that elides, or appears to elide, part of a noun phrase that can be recovered from context.