Definition from Wiktionary, the free dictionary
From Latin, from πυλωρός (pulōros, “gatekeeper”).
- (anatomy) The opening in a vertebrate, including humans, at the lower end of the stomach that opens into the duodenum.
- A muscular or myovascular structure that controls the opening of an orifice or lumen of an organ.
Derived terms 
opening between the stomach and duodenum