drop vent

drop vent

[′dräp ‚vent]
(engineering)
In a plumbing system, a type of vent that is connected to a drain or vent pipe at a point below the fixture it is serving.
McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.

drop vent

In plumbing, a special individual vent which connects to a drain or vent pipe at a point below the fixture served.
McGraw-Hill Dictionary of Architecture and Construction. Copyright © 2003 by McGraw-Hill Companies, Inc.