Merriam-Webster Collegiate Dictionary - churn

 I. noun  Etymology: Middle English chyrne, from Old English cyrin; akin to Old Norse kjarni ~  Date: before 12th century a vessel for making butter in which milk or cream is agitated in order to separate the oily globules from the watery medium  II. verb  Date: 15th century  transitive verb  1. to agitate (milk or cream) in a ~ in order to make butter  2.  a. to stir or agitate violently an old stern-wheeler ~ing the muddy river  b. to make (as foam) by so doing  3. to make (the account of a client) excessively active by frequent purchases and sales primarily in order to generate commissions  intransitive verb  1. to work a ~  2.  a. to produce, proceed with, or experience violent motion or agitation her stomach was ~ing ~ing legs  b. to proceed by or as if by means of rotating members (as wheels or propellers) boats ~ing across the harbor CHURR  intransitive verb  Etymology: imitative  Date: 1555 to make a vibrant or whirring noise like that made by some insects (as the cockchafer) or some birds (as the partridge)  • ~ noun