py·lo·rus 
(pī-lôrəs, pĭ-)
(pī-lôrəs, pĭ-)n. pl. py·lo·ri (-lôrī′)
The passage at the lower end of the stomach that opens into the duodenum.
[Late Latin pylōrus, from Greek pulōros : pulē, gate + ouros, guard; see wer-3 in the Appendix of Indo-European roots.]