Etymology
From Middle English stepsone, stepsune, from Old English stēopsunu (“stepson”), from Proto-Germanic *steupasunuz (“stepson”), equivalent to step- + son.
Cognate with Saterland Frisian Stäifsuun (“stepson”), West Frisian styfsoan (“stepson”), Dutch stiefzoon (“stepson”), German Low German Steevsöhn (“stepson”), German Stiefsohn (“stepson”), Danish stedsøn (“stepson”), Swedish styvson (“stepson”), Icelandic stjúpsonur (“stepson”).