Original: The New Wave of British Heavy Metal (frequently abbreviated as NWOBHM and pronounced) was a heavy metal movement that started in the late 1970s, in Britain, and achieved international attention by the early 1980s.
Simplified: The New Wave of British Heavy Metal (NWOBHM) was a heavy metal movement that started in the late 1970s, in Britain. It was well known around the world by the early 1980s.