While sifting through various Microsoft Operations Framework documents, I came across an interesting definition of process in a document called Using MOF for ISO/IEC 20000: A MOF Companion Guide.

A process is a set of interrelated activities designed to transform inputs into pre-defined acceptable outputs. The benefit of a process-based framework is that you then have a repeatable set of activities in place designed to take the input, modify or change that input, and deliver the desired output. Because the process is documented and repeatable, it is now a tangible item that can be monitored, measured, and improved over time. If you do not like the outcome, you can either change the inputs, change the process activities to improve the output, or change the expectation of what the output is to be. By defining and communicating the expected output, you also control the customer’s expectation (and therefore the customer’s satisfaction).

What I like best about this definition is how it relates the concept of process all the way to the benefits for the end customer. The definition also builds on the tangible nature of defined processes which makes process monitoring, measurement, and improvement possible.

Keep in mind that both MOF and ISO-20000 are process based.