churn

noun

1. a container or contrivance in which milk or cream is beaten, stirred, or shaken to form butter
2. ☆ the occurrence, ratio, or amount of turnover of investments, customers, commodities, etc.

transitive verb

1. to stir, beat, or shake (milk or cream) in a churn
2. to make (butter) in a churn
3. to stir up vigorously
4. to produce (foam, etc.) by stirring vigorously
5. ☆ to cause a rapid turnover of (a client's investments) so that the broker can claim commissions

intransitive verb

1. to use a churn in making butter
2. to move or stir as if in a churn: many ideas churning in his brain