An Etymological Dictionary of Astronomy and Astrophysics
English-French-Persian

Son of the same parents as another person.

M.E.; O.E. brothor; cognate with Du. broeder, Ger. Bruder, Goth. brothar, Skt. bhrātr, Gk. phrater, L. frater, Pers. barâdar, as below, Rus. brat; PIE *bhrater.

Barâdar, from Mid.Pers. brât(ar) "brother;" O.Pers. brata-; Av. brātar- "brother;" cognate with E. brother, as above.