1. : to pass or extend under
underrun and uplifted by advancing masses of colder air
2.
a. : to pass along under in order to examine (a cable)
b. : to separate and put in order the parts of (a tackle)
c. : to take in (a net or trawl line) for emptying and resetting
d. : to lift and empty out (a hose) by walking along and shifting the hold successively along the length
: to flow or persist in a suppressed or underlying stream
II. \\ˈ ̷ ̷ ̷ ̷ˌ ̷ ̷\ noun
1. : undercurrent
2. : a run (as of goods or printed copies) short of the quantity ordered by a customer
3. : the amount by which the actual cut of merchantable lumber falls below a log scale estimate
4. : the lower contact surface of a third rail or trolley wire
Useful english dictionary. 2012.