The epidemiology, risk factors, and biological basis of suicidal behaviors have been the object of an ever–increasing research in the last three decades. During this period, researchers all over the world have identified potential biomarkers of risk and developed several theories about the mechanisms leading to suicidal behavior. However, the lack of common terminology, instruments, and cooperation has been a major deterrent. Today, the community has established the bases for this collaboration and evidence coming from neuroscientific studies can already be applied to the field of suicidology. We present here a potential semiology based on current evidence coming from biological, clinical, and neuroimaging studies.