"帆布经线" can be translated into English as "canvas warp threads" or simply "canvas warp".
Canvas refers to the heavy, durable fabric typically used for sails, tents, and bags.
Warp threads are the longitudinal threads in a woven fabric that run parallel to the length of the fabric. They are the foundational threads that the weft threads are woven through.
So, combining these two terms gives you "canvas warp threads" or "canvas warp" to accurately describe the warp threads in canvas fabric.