WordNet
external orifice
n. the orifice through which urine is discharged [syn: urethral orifice]
Usage examples of "external orifice".
Cursorily, one would say that its respiration apparatus handled oxygen rather than carbon dioxide, and there were odd evidences of air-storage chambers and methods of shifting respiration from the external orifice to at least two other fully developed breathing systems - gills and pores.