Oi!

Oi! is a subgenre of punk rock that originated in the United Kingdom in the late 1970s. The music and its associated subculture had the goal of bringing together punks, skinheads and other working-class youth. The Oi! movement was partly a response to the perception that many participants in the early punk rock scene were, in the words of The Busi...
Found on http://en.wikipedia.org/wiki/Oi!

OI!

Time-honoured warning to pedestrians to move out of harm's way. Predates the bell.
Found on http://www.bikereader.com/contributors/SAM/glossary.html
No exact match found