Wiktionary
vb. (context intransitive English) To come together, to form a crowd.
Usage examples of "crowd up".
Picton turned and came back inside, while Sheriff Dunning and his men gently started to break the crowd up.
And they had better gather this crowd up and take them into a room of one of these ruins and explain and play the discs for them so they wouldn't think the place was full of devils.
And they had better gather this crowd up and take them into a room of one of these ruins and explain and play the discs for them so they wouldn’.
Half a dozen families has their cabins within a mile of each other, and I dunno what in hell they want to crowd up together that way for, it would plumb smother me, but pap says they was always peculiar that way.
If we handle this right, we could build up quite a crowd up there.
At least here, facing the Doge's palace and the lagoon, where not so many people could crowd up against the building, it was easier to hear.