Middle Scots spen, speane, probably going back to Old English *spennan, *spenian, going back to Germanic *spanjan- or *spanjōjan- (whence also Middle Dutch spenen "to wean," Middle Low German spenen, spennen, Middle High German spenen), verbal derivatives from the base of *spanōn-, *spanjōn- "teat, nipple" (whence Old English spane, spanu "teat," Middle Dutch spene, Middle Low German spene, spone, Old High German spunna, Old Norse speni), akin to Lithuanian spenỹs "nipple," Old Irish sine, probably altered from Indo-European *psten- "breast," whence Sanskrit stana- "breast, nipple," Avestan fštāna-, Greek stḗnion "breast"