Thread
Embroidery Thread
Embroidery thread that comes on spools rather than in hanks is usually either made from rayon or polyester and sometimes nylon. It has a higher sheen than regular sewing thread which is often cotton wrapped polyester. Embroidery thread is designed to function in high speed, embroidery machines and comes in a multitude of colours. Many sewers who own embroidery machines will tell you that you just have to find the brand of thread that your machine likes. For seaming, embroidery thread is not designed to be strong as the thread that you use for construction as its purpose is decorative.
Sewing thread can be silk (used in couture sewing), cotton, polyester, cotton wrapped polyester or nylon. 100% cotton is used more for quilting. General garment construction is usually cotton wrapped polyester or polyester. Nylon is sometimes used in speciality applications such as outdoor fabrics. The bigger the weight number, the smaller the thread. General sewing is usually done with 40 wt. And a lot of quilters use 50 wt for piecing. There are other types of speciality thread out there. If you peruse the manufacturer’s websites there is a lot of great information about matching the thread to application and machine needles.