Rate is a term that can refer to three different concepts: the rate as a tribute, the rate as an exchange rate or price control, and the rate as a coefficient or measure of one or more phenomena. As a tribute, rate is a price, amount, measure or percentage in which something has been assessed, such as a tax for certain public services. This term is preferred when a certain proportion between economic variables is relatively stable over time, such as: the birth rate, death rate, etc. In other, more modifiable cases, we speak of "type": interest rate, exchange rate, discount rate, etc.
The rate as a quotient or measure is widely used in demography and economics, among other sciences, as an indicator. For example, in demography, the population growth rate is a measure of the growth of the population of a certain territory in a specified time. In economics, the discount rate is a financial indicator that is used to determine the present value of a future payment.
