τὸ ξύλον, -ου – wood (cut and ready for use), timber. Rarely: a tree.
When I showed you last week the Greek word for „tree“ (τὸ δένδρον) I originally wanted to give you an example from the Bible: the tree of the knowledge of good and evil. But who would have thought of that? A tree is not a tree in the Septuagint! Instead of δένδρα God planted ξύλα in the garden of Eden: τὸ ξύλον usually means „wood“ (as a material) but on rare occasion can also mean the (living) tree. So in the Septuagint „tree of the knowledge of good and evil becomes“: τὸ ξύλον τοῦ γινώσκειν καλὸν καὶ πονηρόν.