Originally wax was something bees made the inside of their hives out of, that people harvested to use. Wax is soft enough to be able to mold it into new shapes, but doesn't melt at room temperature. Liquid wax will burn with a bright light, and is used to make candles out of.
Things that are waxy and similar to beeswax are also called wax. Modern candles are made from paraffin wax. The stuff you sometimes scratch out of your ears is waxy and called earwax. Many cosmetics like lipstick are made mostly from wax.
Wood is what the trunks and branches of trees are made from. Trees get thicker as they grow, so when you cut them down you can see rings of colors in the inside of the tree, like in the picture. When you cut a tree lengthways the rings become lines called grain, which you can see in most things made out of wood.
Wood is used to make houses, furniture and some toys.