@burcinc-- Comorbidity simply means that someone is suffering from two or more conditions or diseases at the same time. The term is not limited to psychiatry. For example, my mom has both diabetes and high blood pressure. That's also comorbidity.
Comorbid psychiatric disorder means the existence of two or more unrelated psychiatric conditions coexisting at the same time. The article gave some good examples, such as an individual suffering from bipolar disorder and general anxiety disorder at the same time. As long as a condition is medically recognized as a separate illness from others, it can be included in a comorbidity assessment. So, to answer your question, yes. Someone with depression and anxiety has comorbidity.
But being labeled with this tag is not a bad thing. It can help doctors determine better and more effective treatment methods. Or it can point to a possible connection between the different disorders and their prevalence.