mid-13c., from O.N. rannsaka "to pillage," lit. "search the house" (especially legally, for stolen goods), from rann "house," from P.Gmc. *rasnan (c.f. Goth. razn, O.E. ærn "house") + saka "to search," related to O.N. soekja "seek" (see
seek). Sense influenced by sack (v.).