A fitting that allows two pipes or nipples to be joined together at an angle of less than 180o, usually 90 o or 45 o. (Slang term for elbow is "ell"). (WLOP)
The Mudblogger (Oilfield, Energy and Related Photographs), Oil Field Glossary, TX, USA 2014. http://mudblogger.com/oilfield-glossary/, (Oil - Amer) {777}