"A couple" means two. It's less specific than the word "two" though. We use it liike this:

We split a couple of appetizers — the grilled octopus and the eggplant dip with pita.

We often use "a couple" along with a number category:

a couple dozen

a couple hundred

a couple thousand

a couple million

You can also use "a few" in the same way:

There were a few thousand people there.