I see this term a lot in the context of software architecture (in phrases like "domain-model", "domain-driven-design" etc.). I have googled it, but I get tons of different definitions. So what is it really?
Note: Some suggest closing the question for it is too broad. I don't think it is. This term is maybe very widely-used, but it doesn't mean that its definition is too broad.
It simply means the problem space you are working in. For example, if you were building an e-commerce website your domain would be "e-commerce" and would involve the processes associated with your client/company's sales practices. So a domain model would be something to represent a product or an invoice or a shipping record.