underflow meaning (ISO) The state in which a calculator shows a zero indicator for the most significant part of a number while the least significant part of the number is dropped. For example, if the calculator output capacity is four digits, the number .0000432 will be shown as .0000. See: arithmetic underflow.
Underflow meaning The lateral motion of water through the upper layers until it enters a stream channel. This usually takes longer to reach stream channels than runoff. This also called subsurface storm flow.