CALMS is a foundational model for DevOps and is a useful starting point for understanding DevOps. DevOps is often (mistakenly) used interchangeably with automation but DevOps is much more than this.
The CALMS model explains this brilliantly the full meaning of the term DevOps:
This diagram is great for reminding teams of the full scope of DevOps.
There are plenty of definitions of DevOps but there is not one, standard definition. It is a broad term and means different things to different people. We are big fans of the CALMS model of DevOps because in the absence of a universal definition it provides us with a clear explanation for the true scope of DevOps.
This diagram is great for making sure that teams within your organisation don't lose site of the bigger picture by focusing on only one of these areas.