Pronunciation: (ob'tu-rāt", -tyu-), [key]
—v.t., -rat•ed, -rat•ing.
1. to stop up; close.
2. Ordn.to close (a hole or cavity) so as to prevent a flow of gas through it, esp. the escape of explosive gas from a gun tube during firing.
Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease.