The ability to do a task, performance, or execution; a set of functions that something is able or equipped to perform.
The presence of a functional group.
In United States trademark law, the tendency of a product design to serve a function other than identification of the product, preventing that design from being protected as a trademark.
The ability or capacity to perform something
Concentration; strength
Sexual virility: the ability to become erect or achieve orgasm.
Potentiality, ability, capacity.
Power, authority.