The Collaborative International Dictionary
Obturate
Obturate \Ob"tu*rate\, v. t. [imp. & p. p. Obturated; p. pr. & vb. n. Obturating.] [L. obturatus; p.p. of obturare.] To stop or close, as an opening; specif., (Ordnance), to stop (a gun breech) so as to prevent the escape of gas in firing.
Wiktionary
obturate
vb. 1 To block up or obstruct. 2 # To stop up (a gun breech) so as to prevent the escape of gas when firing.