Cash per share is calculated by taking all the cash and short term investments of the company and dividing that number by the total shares outstanding.
The “cash” part of cash per share includes cash and short-term investments i.e. any liquidity it has in the books; money that a firm has on hand, not borrowing or financing activities.
You want to stay away from companies with too high or too low cash per share. Too high cash per share indicate that the company is wasting shareholders money by not putting them to use or giving them back to the share holders as dividend. Too low implies that the company may be in some serious trouble if it suffers a setback or unforseen expenditures.
A stock trading below its cash per share may be a good investment, particularly if the stock has zero or little debt.
This article contained the definition of cash per share.