slank /ˈsleɪ̯ŋk/ noun1 •(dialect, US) A depression, a low place in the ground, especially one at the side of a river, lake, or cove which is filled with water during freshet(s).Passaic, N. J. - The storm will cause great delay in filling in the slank. The dirt which the workmen have been throwing in was washed away into the river. — 1913 formsslanks