Ball Bearing : A bearing comprising two steel rings or races, one usually pressed onto a shaft, the other supported in a housing, separated by hardened steel balls running in grooves in the races
Ministry of Business, Innovation and Employment, Glossary of terms and acronyms, Wellington, New Zealand 2010. http://wwwsosh.govt.nz/resources/glossary-u.shtml, (Occupn Hlth and Sfty - Brit) {530}