overflow verb (TOO FULL) C2 [ I or T ] When a liquid overflows, it flows over the edges of a container, etc. because there is too much of it: The milk overflowed when I poured it into the jug. Because of heavy rain, the river may overflow its banks. [ I or T ]

(of a liquid) to flow over the edges of a container because there is too much, or to contain more of something than can be held: [ T ] Because of the heavy rains, the river overflowed its banks. [ I ] The sink quickly overflowed, flooding the room. [ I ] The train platform was overflowing with passengers.

1 : to cover with or as if with water : inundate 2 : to flow over the brim or top of the river overflowed its banks 3 : to flow over bounds the creek overflows every spring