Real Dictionary

churn
A churn is a container which is used for making butter.
verb: If something churns water, mud, or dust, it moves it about violently.

churn in American English
a container or contrivance in which milk or cream is beaten, stirred, or shaken to form butter
to stir, beat, or shake (milk or cream) in a churn
to use a churn in making butter
intransitive verb: to operate a churn
noun: a container or machine in which cream or milk is agitated to make butter
transitive verb: to agitate in order to make into butter

churn in British English
noun: a large container for milk
verb: to stir or agitate (milk or cream) in order to make butter

churn in Insurance
verb: If a bank or broker churns a contract or policyholder, they encourage a client to change investments or policies in order to increase commissions at the client's expense.