When it is often called a growth rate or rate of expansion. When it is often called a decay rate or shrink rate, where the idea that it is a "rate" comes from interpreting as a sort of discrete time variable. When an application area has specialized vocabulary for specific types of growth, expansion, shrinkage, and decay, that vocabulary will also often be used to name parameters of geometric series. In economics, for instance, rates of increase and decrease of price levels are called inflation rates and deflation rates, while rates of increase in values of investments include rates of return and interest rates.
when it is often called a growth rate or rate of expansion when it is often called a decay rate or shrink rate where the idea that it is a "rate" comes from interpreting as a sort of discrete time variable when an application area has specialized vocabulary for specific types of growth expansion shrinkage and decay that vocabulary will also often be used to name parameters of geometric series in economics for instance rates of increase and decrease of price levels are called inflation rates and deflation rates while rates of increase in values of investments include rates of return and interest rates