The answer to the crossword question “Treat, as wood is STAIN” is the word “stain“. Staining is a process where a substance is applied to wood to change its color or to make it more resistant to water, dirt, or other types of damage. Staining is often used to enhance the natural beauty of wood or to make older wood surfaces look new and fresh. Different types of stains are available, including oil-based, water-based, and gel stains, and each one has its own unique benefits and features. Regardless of the type of stain used, the end result is a beautiful and durable finish that can protect the wood for years to come.