The threads that are stretched taut across the loom before weaving begins are called:

The threads that are stretched taut across the loom before weaving begins are referred to as warp. In weaving, the warp threads serve as the foundational structure of the fabric. They run lengthwise on the loom and provide the necessary support for the interweaving process to occur.

When the weaver operates the loom, the weft threads are inserted horizontally through the warp threads, creating the textile. This interplay between the warp and weft is essential to forming various patterns and fabrics. The warp's tension must be maintained throughout the weaving process to ensure a smooth and even finished product.

The other terms mentioned do not specifically refer to the threads on the loom before weaving. Weft refers to the threads that are woven across the warp, tension refers to the amount of stretch in the threads, and count typically relates to measuring the number of threads per unit, but does not describe the threads themselves. This understanding of terminology is vital for anyone studying weaving or fabric construction in art.