the replacement of an edge or solid angle (as in cutting a gemstone) by a plane (especially by a plane that is equally inclined to the adjacent faces)(noun.act)
source: wordnet30
the act of cutting short(noun.act)
Example: It is an obvious truncation of the verse.
They were sentenced to a truncation of their limbs.
source: wordnet30
The act of truncating, lopping, or cutting off.(noun)