Depressive disorder, also known as clinical depression or major depressive disorder, is a mental illness that affects millions of people worldwide. While the term depressive disorder is commonly used, there are several synonyms that can describe this condition. Some of these include mood disorder, affective disorder, depression, melancholia, despair, and dysthymia. These terms refer to the different types and severity of depression, ranging from mild to severe. It is important to note that depression is a serious medical condition that requires professional help, and using appropriate terminology helps to reduce stigma and increase understanding and support for those affected by it.