You have seen "MSK" in an article on the public cloud. Does the "K" stand for "Key"? What does MSK stand for?
MSK stands for "Managed Streaming for Kafka". It is an Amazon product.
"Amazon Managed Streaming for Apache Kafka (Amazon MSK) is a fully managed service that enables you to build and run applications that use Apache Kafka to process streaming data. Amazon MSK provides the control-plane operations, such as those for creating, updating, and deleting clusters." (Taken from https://docs.aws.amazon.com/msk/latest/developerguide/what-is-msk.html.)