propagation
prop.a.ga.tion \.pra:p-*-'ga--sh*n\ \-shn*l, -sh*n-*l\ n : the act or action of propagating : as : increase (as of a kind of organism) in numbers : the spreading of something (as a belief) abroad or into new regions : DISSEMINATION : enlargement or extension (as of a crack) in a solid body - prop.a.ga.tion.al aj