utility

utility is on the Academic Word List.

Noun

(countable); (usually plural) Utilities are the basic services that come to your house, such as electricity, phone, and water.
The government is raising prices on drugs, beer and most public utilities.
(countable) A utility is a basic computer program that handles things like copying disks and setting up printers.
(uncountable) Something's utility is how useful it is.
The design was to maximise the utility of the book as a whole.