A unit rate is a ratio that has a denominator of 1. A unit rate is also called a unit ratio. (They mean the same thing.)
\frac{5}{4} and 3:8 and 40\mbox{ to }10 are ratios, but they are not unit ratios.
\frac{1.25}{1} and 0.375:1 and 4\mbox{ to }1 are unit ratios.
Any ratio can be converted into a unit ratio by dividing the numerator and the denominator by the denominator.
