Rate

Rate or rates may refer to: Rate (mathematics), a specific kind of ratio, in which two measurements are related to each other
Naval rating, a term used to designate speciality or rank of naval officials
Rate of a ship, a term indicating a sail ship's firepower in the British Royal Navy
Rates, a Portuguese parish and town located in the municipality of Póvoa de Varzim
Bit rate, number of bits that are conveyed or processed per unit of time

In math and finance:
Rate function, a function used to quantify the probabilities of rare event
Rates (tax), a type of taxation system used to fund local government
Exchange rate, specifies how much one currency is worth in terms of the other

In human growth:
Birth rate, the natality or childbirths per 1,000 people per year
Mortality rate, a measure of the number of deaths in some population