To flow or run over the brim or edge of a container or boundary. The river overflowed its banks after the heavy rain.
To be so full that the contents spill over the top. The pot overflowed when she forgot to turn off the stove.
To fill or cover completely, often to excess. The inbox overflowed with unread messages after the weekend.
To extend beyond limits or capacity. The crowd overflowed into the streets during the parade.