From Proto-Baltic *swaynya-, from Proto-Indo-European *swoini, probably meaning “ours,” “one of us”, from *swe-, *swo- with an extra in, from the reflexive pronominal stem *se- (“one's own”) with an extra -we, -wo (whence also Latvian savs). The meaning probably went from “one of us, one of our relatives” to “one who has become a relative (by marriage)” and was then restricted to “brother-in-law.” Cognates include Lithuanian sváinis (“wife's sister's husband”), Old High German swein (“servant, shepherd”) (< “one of us”), Messapic veinam (“one's own (acc.)”).
- brother-in-law (one's wife's brother or one's husband's brother; also, one's sister's husband, or one's wife's sister's husband)
- tev pašam māsa un svainis strādā kaut kur kolhozā ― your very sister and brother-in-law work somewhere in a collective farm
- Līzbetei daudz radu nebija... pilnīgi cerams, ka svainis Līdaks ar māsu Gerdu bērēs nebūs ― Līzbete didn't have many relatives... it can certainly be hoped that (her) brother-in-law Līdaks and (her) sister Gerda won't be at the funeral
|singular (vienskaitlis)||plural (daudzskaitlis)|