1. (

• collapse ,
• fall_in ,
• cave_in ,
• give ,
• give_way ,
• break ,
• founder

) 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" ;

2. (

• fall_in ,

) to take one's place in a military formation or line; "Troops fall in!" ;

3. (

• join ,
• fall_in ,
• get_together ,

) become part of; become a member of a group or organization; "He joined the Communist Party as a young man" ;