- Austrian monk and botanist.
- a male given name, form of Mandel.
- Gregor Johann (ˈɡreːɡɔr joˈhan). 1822–84, Austrian monk and botanist; founder of the science of genetics. He developed his theory of organic inheritance from his experiments on the hybridization of green peas. His findings were published (1865) but remained unrecognized until 1900
