ˈ ̷ ̷ ̷ ̷+ˌ ̷ ̷ ̷ ̷ noun
( -s )
Etymology: probably from French, from aut- + frettage
: the application of such interior pressure to the bore of a heavy ordnance gun as will deform the inner layers of steel beyond the elastic limit that would be reached by the explosion of any charge to be used subsequently in the gun