Why does -u mean remember for git push [-u]?

Question

In the manual it states that -u will tell git to remember where to push to.

However, I think this is a strange abbreviation. -r would make more sense.

It works fine I'm just wondering where these abbreviations come from.

Answer 1

it means

--set-upstream

and that means:

git push --set-upstream sets the default remote branch for the current local branch.

(see this answer)