1.
If you say that a letter stands for a particular word, you mean that it is an abbreviation for that word.
What does EU ~?
PHRASAL VERB: V P n
2.
The ideas or attitudes that someone or something stands for are the ones that they support or represent.
The party is trying to give the impression that it alone stands for democracy...
= represent
PHRASAL VERB: V P n
3.
If you will not ~ something, you will not allow it to happen or continue.
It’s outrageous, and we won’t ~ it any more.
PHRASAL VERB: with neg, V P n