The terms process and business process, in particular, are sometimes used lightly and without thinking too much about what those terms actually mean.
Drawing upon and thinking in terms of the concept of a value chain (i.e., a set of activities designed to create a product or service that has value to a customer) some time ago I came up with this definition of what constitutes a process, not just when it comes to business and market value, but also with regard to processes in computing and software (which might or might not be related to a business purpose in a more narrow sense of the word):
A process is a directed sequence of dependent, repeatable, uniform steps that are necessary for accomplishing a task in a value creation chain.