1
general::
Phrase(s): fall in
to line up in a row, standing shoulder to shoulder. • The Boy Scouts were told to fall in behind the leader. • The soldiers fell in quickly., Phrase(s): fall in(to step)
to get into the same marching pattern as everyone else as regards which foot moves forward. (Everyone should be moving the same foot forward at the same time.) • I just can’t seem to fall into step. I am very uncoordinated. • Fall in! March with the others!, Phrase(s): fall in(to something)
to drop into something. • The rabbit fell into the hole and was trapped. • It went right up to the hole and fell in.
McGrawhill's American Idioms And Phrasal Verbs
2
general::
1. Take one's place in formation or in the ranks, as in The sergeant ordered the troops to fall in. A related expression is fall into, as in They all fell into their places. [Early 1600s] Also see FALL INTO. 2. Sink inward, cave in, as in The snow was so heavy that we feared the roof would fall in. [Early 1700s] Also see under DROP IN; the subsequent idioms beginning with FALL IN; FALL INTO.
American Heritage Idioms