Wiktionary
vb. 1 To join (a group of people). 2 To meet with (something). 3 To accept (a set of generally agreed rules, or a suggestion).
Usage examples of "fall in with".
Rita didn't seem the type to fall in with Roger's nefarious plans, if indeed he had any.
Having given in to Ben's brutal mood of an hour ago, she found it easier to fall in with his new plan.
Then pieces of the archway began to drop, and the lower masonry of the building to fall in with the rumbling sound of coals being shot into a cellar.
So it was that when Bubbler Graham phoned after dinner he was more ready to fall in with her suggestion that they should go to the movies than he would otherwise have been.
As I went to fall in with my company I met the regimental postman who handed me a letter which I saw at a glance was from my beloved Louie.
When it swept around her, she would fall in with the others, then the hunters would ride on.
He also thought enough of the Grainger legend to fall in with whatever I decided.
There is a marked difference between the behaviour of the lower people of the eastern cities and those whom you fall in with in this town: they are much less civil in their behaviour here.
The party had proceeded many miles before they arrived at the spot where Malachi thought that they would fall in with some venison, which was the principal game that they sought.
So Ruggedo, cleverly concealing his displeasure, pretended to fall in with their plans and after the pirates, under the direction of Binx and Peggo, had stored all the stuff worth taking aboard the Sea Lion, he called a council in the Yellow Courtyard.