noun
solid wood; natural wood
Refers to wood that is not veneered or laminated, i.e., a single piece of natural timber. Common in furniture and construction contexts.
このテーブルは無垢材でできている。
This table is made of solid wood.
無垢材の床は温かみがある。
A solid wood floor has a warm feel.
集成材 is laminated or glued laminated timber, made from smaller pieces bonded together, unlike 無垢材 which is one solid piece.
Compound of 無垢 (むく, 'pure, unadulterated') + 材 (ざい, 'material, lumber'). The term literally means 'pure material', referring to wood that is not mixed or layered with other materials.