Something collapses when all its parts fall down or give away. A building or a bridge collapses when it breaks and all its parts fall down. A person collapses when they are tired and they fall into a chair or onto a bed.
He was so tired, he just collapsed onto that chair.
You just learned a few sample words from this lesson. This lesson contains more flashcards and is part of the course "Academic Word List"
The course includes a total of 10 Lesson.
Try the course free of charge and without obligations :)