The abbreviation mAh stands for milliamperes/hour and tells the capacity of the battery and is the product of current and time, usually quoted at the ten hour rate.
For instance: 1500 mAh battery can deliever 1500 mA (1.5A) for 10 hours, or approximately pro-rata. A 3000 mAh hour battery can deliver 3000 mA (3A) for 10 hours, or approximately pro-rata.
The time for higher discharge currents will be less than that expected because of the batteries inevitable internal resistance, and the heat generated. So a 1500 mAh battery will deliver 1500mA for less than 1 hour