Dictionary.net

• A conical valve, opening outward, to close the mouth of a pipe which passes through the side of a vessel below the water line.

2010 - New Age Dictionary Database
By Oddity Software

• A conical valve, opening outward, to close the mouth of a pipe which passes through the side of a vessel below the water line.

1913 - Webster's Revised Unabridged Dictionary
By Noah Webster.