Stranded cotton (or 'Floss,' as known in America) is often referred to as '6 Strand Cotton' because each length of mercerised cotton is made up of six smaller strands, which are then separated when required for use. Put simply, it's the embroidery thread you use to create your cross stitch designs.
Stranded cottons come in skeins – a specific way that the lengths of thread are wound up, loosely coiled and knotted. There are hundreds of cotton colours available to allow you to find a match for a whole host of projects, however a certain thread colour is often recommended in your chart's key.
Not only does a chart suggest colours, but it also tells you how many strands you need to use for each section of the design – the more strands used, the heavier and bolder the stitch. The fewer the threads, the more refined and detailed that section of the design can be.
Thread cutting in cross stitch requires specialist scissors, commonly referred to as embroidery scissors. These small, thin and sharp scissors are designed to trim threads quickly, cleanly and very closely to the fabric, and are available in a whole host of shapes.
For example, you may come across straight embroidery scissors, bent embroidery scissors (for use with embroidery hoops), or spring-loaded embroidery scissors, to name a few. But ultimately, the ones you choose depend on the qualities you personally require in a pair of embroidery scissors.