- (intransitive) To fall to the ground. To collapse.
- Ring a-ring o' roses, / A pocketful of posies. / A-tishoo! A-tishoo! / We all fall down. — traditional nursery rhyme (British version)
- The beams supporting the roof had rotted, causing the entire house to fall down.
- 1945 August 17, George Orwell [pseudonym; Eric Arthur Blair], chapter 7, in Animal Farm: A Fairy Story, London: Secker & Warburg, OCLC 3655473 ↗:
- Out of spite, the human beings pretended not to believe that it was Snowball who had destroyed the windmill: they said that it had fallen down because the walls were too thin.
- (nautical) To sail or drift toward the mouth of a river or other outlet.
- (intransitive, figurative) To fail.
- That is where your reasoning falls down.