Lignification \Lig`ni*fi*ca"tion\ (l[i^]g`n[i^]*f[i^]*k[=a]"sh[u^]n), n. [Cf. F. lignification. See {Lignify}.] (Bot.) A change in the character of a cell wall, by which it becomes harder. It is supposed to be due to an incrustation of lignin. [1913 Webster]