An Etymological Dictionary of the German Language/Segel
Segel, n., ‘sail,’ from the equiv. MidHG. sëgel, OHG. sëgal, m.; comp. OSax. sëgel, n., Du. zeil, n., AS. sëgel, m. and n., E. sail, OIc. segl, n., ‘sail’ (Goth. *sigla- is not recorded). The word cannot have been borrowed from Lat. sagulum, ‘military cloak,’ on account of the sounds, and because no other OTeut. nautical expressions have been derived from Lat.; besides, sagulum is not a naut. term. Segel (Teut. *segla-) looks very much like a Teut. term (comp. Mast), yet the root cannot be ascertained. From the Teut. cognates Fr. cingler and Span. singlar, ‘to sail,’ are derived.