What is the meaing of ply?

"Ply" can refer to the layers or thickness of a material, such as in plywood, where multiple layers are glued together for strength. In the context of textiles, it describes the number of strands twisted together to form yarn. Additionally, "ply" can mean to work diligently or to apply oneself to a task. The specific meaning often depends on the context in which it is used.