The history of the word panic, of the concepts of Panic attack and of Panic Disorder is a complex one. The adjective word panic, derived from the Greek, stressed initially the intensity of a feeling of unjustified, individual or collective, fear, similar to the reaction provoked, according to the mythology, by the intervention of the God Pan. In their present meanings, the concepts belong to the group of anxiety states, the Panic attack being a symptom characterized by a paroxysmal anxiety which may appear in various psychopathological states, whereas the Panic Disorder is a nosological category whose diagnostic criterium is the appearance, with a definite frequency, of Panic attacks. The disorder is frequently associated to agoraphobia considered, when it exists, as a complication. It is necessary to describe, in addition to the terms and concepts related to panic, the history of the terms angoisse and anxiété (and of the equivalent ones in English and German, since many studies dealing with the subject have been written in those languages) and the history of agoraphobia. The history of the word panic and of the psychiatric concepts to which it is applied today are partially different as are the current meanings of the adjective and the substantive (and today of the verb to panic) from their technical meanings. In the technical vocabulary the substantive word refers on the one side to an abnormal group behaviour whose mechanisms, when it appears in an army by also elsewhere, are studied by social psychopathology. On the other side it has been used until recently, but only in psychiatric texts written in English, for describing acute individual states of high anxiety, eventually associated with other symptoms, and considered as pertaining-in contrast to the Panic attack in its present meaning-to various psychiatric illnesses (melancholic panic, homosexual panic). A description of states similar in their aspects, including the association to agoraphobia, to the present Panic attack, may be found in the literature of the XIXth century. Essential in this respect is the description of anxiety neurosis which Freud isolated in 1895 from neurasthenia and defined by the coexistence of a state of moderate and permanent anxiety and of anxiety attacks, whose manifestations were identical to those of the present Panic attack. Under the influence of Klein's researches which, from 1962 on, demonstrated the differential reactivity to drug therapy of its two component parts, anxiety neurosis was divided in two distinct entities. The term Panic attack-for reasons given in detail by the paper-was proposed for the acute anxiety attack, whereas the state of moderate and permanent anxiety, considered as a completely independent disorder, received the name of Generalized Anxiety Disorder. The concept, with its corresponding nomenclature, was adopted initially in the United States by the RDC (1975), then by the DSM-III (1980). It is accepted today and has been the source of a large number of investigations about its semiological, nosological, epidemiological, etio-pathogenic and therapeutic aspects which fall outside of the scope of this paper.