lignify

Etymology

From Latin līgnum (“wood”) + -ify.

verb

1. (intransitive) To become wood.
2. (intransitive, botany) To develop woody tissue as a result of incrustation of lignin during secondary growth.
3. (intransitive, by extension) To become rigid or fixed, like something made of wood.
4. (transitive) To turn into wood; to make ligneous.