Rost \Rost\, n. See Roust. [Scot.] --Jamieson.
Source: Webster's Revised Unabridged Dictionary (1913)
Roust \Roust\, n. [Cf. Icel. r["o]st an estuary.] A strong tide or current, especially in a narrow channel. [Written also rost, and roost.] --Jamieson.