A unary function from quantities to quantities that is an extension of the arithmetical operation of squaring to measurable ScalarIntervals generally. (Squared Fn SCALAR) is by definition equal to SCALAR multiplied by itself: (Times Fn SCALAR SCALAR).

For example, (Squared Fn 9) is equal to 81 and (Squared Fn (mile 3)) is equal to (square mile 9).

See also Squared Fn's quasi-inverse, Square Root Fn.