NUM, the /ˌen juː ˈem/ BrE AmE abbreviation for
the National Union of Mineworkers; a ↑ trade union in the UK for ↑ miner s and other people who work in the ↑ mining industry. Until the 1984–5 miners’ ↑ strike , it was an important union, but it lost a lot of power after many mines were closed.