couplenoun US /ˈkʌp·əl/
couple noun (SOME)
two or a few things that are similar or the same, or two or a few people who are in some way connected:
I’m packing a couple of sweaters in case it gets cold.
I've literally never heard it used that way. A couple is two and three or more is a few, in my experience, like we call two people a couple.
... According to Oxford, that's an informal usage, which makes sense to me at least in the UK. I can't imagine why anyone would use couple for three or more when we already have words for that and it renders "couple" less precise in meaning. How strange.
A couple means a pair. Days don't ordinarily come in pairs, so "a couple of days" is not taken literally. When a number is not taken literally, it is taken as approximate. But approximately two means two plus or minus a fraction and people don't like fractions, so approximately two isn't taken literally either. That's why a couple of days means a few days.
This sentence completes day 613 for me in my Duolingo streak. Most of you know that 613 is a very significant number for Jews, the number of Commandments in the Torah. That's how I feel right now, as if I had completed all 613 Commandments. Fun to complete that with an exercise that has several amusing posts. So thank all of you who participate. Dec. 19, 2019.