Aida cloth (sometimes called Java canvas) is an open, even-weave fabric traditionally used for cross-stitch embroidery. Aida fabric is one of the most widely used cross stitch fabrics. Made from 100% cotton, Aida is a particularly good choice for beginners because the wide, open weave makes the holes easy to see. Aida was created specifically for cross stitch
The higher the number, the smaller the stitches will be, because there are more stitches in each inch.