Real Dictionary

capacity
Your capacity for something is your ability to do it, or the amount of it that you are able to do.
uncountable noun: The capacity of something such as a factory, industry, or region is the quantity of things that it can produce or deliver with the equipment or resources that are available.

capacity in American English
the ability to contain, absorb, or receive and hold
adjective: reaching maximum capacity
noun: the ability to receive or contain

capacity in Automotive Engineering 1
noun: The capacity of an engine is its size or power, expressed in Europe as cubic centimeters or liters, and in the US as cubic inches.

capacity in Automotive Engineering 2
noun: The capacity of a container such as a fuel tank is its volume, or the amount of liquid it can hold, measured in units such as quarts or gallons.

capacity in British English
noun: the ability or power to contain, absorb, or hold

capacity in Electrical Engineering
noun: The capacity of a generating unit, generating station, or other electrical apparatus is the maximum load that it can carry.