We have prepared a list of terms, wich might behelpful while

Marketing, sales and business glossary

Churn rate

The measurement, which gives you information how many customers you retain and what value they present. You need to divide the number of customers you’ve lost by the total number of customers that you had at the beginning of the measured time frame.
Read more: https://www.investopedia.com/terms/c/churnrate.asp#ixzz5KIRSx5Bd