churn (n.) Look up churn at Dictionary.com
Old English cyrin, from Proto-Germanic *kernjon (cognates: Old Norse kirna, Swedish kärna, Danish kjerne, Dutch karn, Middle High German kern); probably akin to cyrnel "kernel" (see kernel) and describing the "grainy" appearance of churned cream.
churn (v.) Look up churn at Dictionary.com
mid-15c., chyrnen, from churn (n.). Extended senses are from late 17c. Intransitive sense is from 1735. Related: Churned; churning. To churn out, of writing, is from 1902.