What Is a Service?
With ITIL® 4 the definition of a service is:
Services: A means of enabling value co-creation by facilitating outcomes that customers want to achieve, without the customer having to manage specific costs and risks.
It’s a little different to, and more detailed than, what you (and I) might usually say; i.e. something like:
“A service is something that meets a need or fulfills a demand.”
Or just “A SERVICE is an action that a person does for someone else.” (KidsEcon Posters)