Definition: fall down, as if collapsing
Usage: The tower of the World Trade Center tumbled after the plane hit it
Similar words: go down, come down, fall, descend
Definition: move downward and lower, but not necessarily all the way
Usage: The temperature is going down; The barometer is falling; The curtain fell on the diva; Her hand went up and then fell again
Definition: cause to topple or tumble by pushing