1. To convert or to change something into rocky substances: In order to petrify wood, there needs to be an environment without oxygen, but with minerals, which then fill the cells of the tree and convert it into a very hard material, such as a stone.
2. To paralyze someone with astonishment, horror, or another strong emotional situation that makes someone rigid or unable to move: Jack was totally petrified and speechless when he lost his job and his wife at the same time.