Seat height is the distance from the floor to the seat. Choose your seat height by determining whether you want your feet to touch the ground or to be placed on a chair rung.
Like your feet to have contact on the ground? Then a seat height of 22" or less is what you are looking for.
If you like to prop your heels on a chair rung when sitting, then seat heights of 23" or higher is what you're looking for.
An adjustable seat height provides a happy medium since the seat height can be adjusted.