1: ξύλον
(Strong's #3586 — Noun Neuter — xulon — xoo'-lon )

denotes "timber, wood for any use" 1—Corinthians 3:12; Revelation 18:12 (twice). See STAFF , STOCKS , TREE.

2: ὕλη
(Strong's #5208 — Noun Feminine — hule — hoo'-lay )

denotes "a wood, a forest," James 3:5 (AV, "matter," marg., "wood"). See MATTER , Note (3).