obturation noun. 
[ɒbtjʊ'reɪʃ(ǝ)n] E17.[Late Latin obturatio(n-), formed as OBTURATE: see -ATION.]The action of stopping something up; the obstruction of an opening or channel; 
spec. the sealing of the breech of a gun. 
 [TahlilGaran] English Dictionary ▲