Brain death is a term used to describe the irreversible cessation of all brain functions. There are several synonyms used interchangeably to describe the same condition. Some of the commonly used synonyms for brain death include irreversible coma, cerebral death, and total brain failure. Another synonym that is frequently used is the term "brain stem death," referring specifically to the destruction of the brain stem, which is responsible for controlling essential life functions such as breathing, heart rate, and blood pressure. In summary, though there are multiple ways to describe brain death, they all refer to the complete and permanent loss of all brain function and a permanent lack of consciousness.