The term 'WOOD ALTERNATIVE' can be solved by the four-letter word 'IRON'. IRON is a strong, durable material that has been used for centuries as an alternative to wood in many applications. It is often used in construction, furniture, and other items where strength and durability are important. IRON is also used in many industrial processes, such as smelting and forging. IRON is a popular choice for wood alternatives because it is relatively inexpensive and easy to work with.