Origin: Germanic Old English prefix
Overflow has 6 different meanings across 2 categories:
a large flow
"The mountain river overflowed after days of heavy rain, turning the valley into a rushing stream."
The spillage resultant from overflow; excess.
"The overflowing cup left a small puddle of liquid on the table."
In plain English: Overflow is when something fills up so much that it spills over its edges.
"The crowd overflowed into the street when the movie ended early."
Usage: Use this noun to describe liquid that spills out because it exceeded its container's capacity, such as water overflowing a cup. It specifically refers to the physical act or result of filling something beyond its limits rather than an abstract surplus.
overflow with a certain feeling
"The children bubbled over with joy"
"My boss was bubbling over with anger"
To flow over the brim of (a container).
"The heavy rain caused the river to overflow its banks and flood the nearby fields."
In plain English: To overflow means to spill over when there is too much of something inside a container.
"The cup was so full that water overflowed onto the table when I took another sip."
The word comes from Old English oferflōwan, which literally meant "to flow over." It entered Middle English as a combination of the prefix over- and the verb flow.