Expression used in online discussion forums relating to
mental illness. Originally referred to the time that
depression set in, later used conversely by survivors to indicate when their recovery was complete. This confusion has seen it fall out of favor in many circles.
Derived from "d-day", the storming of Normandy on June 6, 1943, and the fact that the word "
depression" is often abbreviated to "D" in such forums, as people suffering from "D" have little energy and typing the whole word could be tiring.