c.1150, "young man attendant upon a knight," from O.N. sveinn "boy, servant, attendant," from P.Gmc. *swainaz "attendant, servant," prop. one's own (man), from PIE *swoi-no-, from base *swe- "oneself, alone, apart" (see idiom). Cognate with O.E. swan "shepherd, swineherd,"