Cross stitch fabric count
Count tells you how many stitches fit in an inch, after you account for how many fabric threads each cross covers.
Aida and evenweave
On Aida, the count is the stitch count per inch. Fourteen-count is a common beginner cloth. Other real counts include 11, 16, 18, and 20, and finer counted fabrics continue through 22, 25, 28, 32, 36, and 40.
Those presets are not exclusive to one cloth type. A custom count is always allowed.
Stitching over two
Evenweave and linen are often stitched over two threads. Effective stitches per inch equal the fabric count divided by the threads each cross covers. Twenty-eight-count over two behaves like fourteen-count over one.
A worked check: 120 by 80 stitches on 32-count over two finishes at 7.5 by 5 inches.