what does ud mean on a birth certificate

[lyall]

found u.d on a birth certificate under a birth address does anyone know what this means please

[jackthehat]

Urban District

[echokilo]

Definition for you: (Government, Politics & Diplomacy) (in England and Wales from 1888 to 1974 and Northern Ireland from 1898 to 1973) an urban division of an administrative county with an elected council in charge of housing and environmental services: usually made up of one or more thickly populated areas but lacking a borough charter