e/Guard lock

Information
has gloss	eng: A control lock, or guard lock differs from a normal canal lock in that its primary purpose is controlling variances in water level rather than raising or lowering vessels. A control lock may also be known as a tide lock where it is used to control seawater entering into a body of fresh water.
lexicalization	eng: control lock
lexicalization	eng: Guard lock
instance of	(noun) enclosure consisting of a section of canal that can be closed to control the water level; used to raise or lower vessels that pass through it lock chamber, lock

Media
media:img	T J OBrien Lock and Dam.jpg