It is the current assets of a company, less its inventory and divide by current liabilities. The number is designed to show a companies ability to meet it's current obligation in the short term.
The quick ratio is calculated by dividing current assets minus inventories by current liabilities. It measures a firm's liquidity and ability to meet its near term obligations.
(Current assets - Inventory) / Liabilities. It basically shows if a company can handle its current debts. Higher ratios are better since more assets and less liability equals better financial strength.