Are there any specific rules that restrict the use of "couple" and "couple of"?
I have a couple of months left.
versus
I have a couple months left.
Are the both sentence above correct and formal? and if we are talking about other object —aside from time/duration — , are "couple" and "couple of" still interchangeable?
Best Answer
Conversationally, I would say there is no difference. Either one of those could be used, and you would be understood.
However, the word couple has an interesting nuance. Strictly speaking, it means two, or a pair. However, the idiom a couple of can be used to mean a small number of, or a few.
Collins brings this out rather nicely, for example. Under its entry for couple we find:
and under its entry for a couple of, we see:
So, if you were writing in some formal setting (like an official resumé, for example), I would avoid using couple to mean "roughly two or three," and use a couple of instead. However, if you meant to convey "two and only two," then you could feel free to use couple:
That said, many readers won't analyze the difference between these two so closely, so you still risk ambiguity. You might be better off saying:
The use of "a couple" makes the statement sound very inexact, no matter how Collins might define these words.