Which part of the stem tissue is "wood" made from?

The tissue that wood is made of is xylem. It is a very important tissue for vascular plants. Why? Because of it's basic function, which is in fact to transport water from roots to shoots and leaves. However it also has another function, which is to transports some nutrients. Also, the very word, xylem, is derived from Greek, and it means "wood", and the best-known xylem tissue is in fact wood.