[ verb ] break down, literally or metaphorically
"The wall collapsed" "The business collapsed" "The dam broke" "The roof collapsed" "The wall gave in" "The roof finally gave under the weight of the ice"
Used in print(Hampton Stone, The Man Who Looked Death...)
He adjusted the hat , lifted the horn to his lips as_though it were a flute , and fell_in alongside our fingerprint_expert to cavort with him .
[ verb ] (military) to take one's place in a military formation or line
"Troops fall in!"
Used in print(Donald J. Plantz, Sweeney Squadron....)
Greg rumbled down the rough metal taxi_strip , and one_by_one the seven members of his flight fell_in behind him .