A couple is describing "2" of a certain thing. Sometimes it can be more than 2, but a small amount. I want a "couple" of donuts. That "couple" is cute (Boyfriend/Girlfriend). A pair is describing something that comes in "2". Some words use "pair" even if it's one item though. I will a buy a "pair" of socks (socks come in 2, usually we don't buy 1 sock). That's a nice "pair" of shoes! Ex. of using "pair" with one item: Bring a "pair" of shorts to the swimming pool.

difference between pair and couple is quite difficult......... couple may be "two partners in a romantic or sexual relationship" or "two of same kind considered together" or "small in number " pair :- two similar or identical things taken together. two people in a relationship. that's all I found.!!!!!!!!