Definition of mother's brother in English:

mother's brother

noun

Anthropology
  • A maternal uncle, usually opposed to a paternal uncle with reference to relative status in kinship affairs and social customs.

Origin

Late 19th century; earliest use found in Lewis Henry Morgan (1818–1881). From the genitive of mother + brother [interjection].

Pronunciation

mother's brother

/ˌmʌðəz ˈbrʌðə/