1.  departure(n = noun.act) going, going away, leaving - the act of departing;
is a kind of act, deed, human action, human activity
has particulars: breaking away, farewell, leave, leave-taking, parting, french leave, disappearance, disappearing, withdrawal, sailing, boarding, embarkation, embarkment, exit, despatch, dispatch, shipment, takeoff
Derived forms verb depart₁, verb depart₄, verb depart₃

2.  departure(n = noun.event) deviation, difference, divergence - a variation that deviates from the standard or norm; "the deviation from the mean"
is a kind of fluctuation, variation
has particulars: discrepancy, variance, variant, driftage, flection, flexion, inflection
Derived form verb depart₂

3.  departure(n = noun.event) exit, expiration, going, loss, passing, release - euphemistic expressions for death; "thousands mourned his passing"
is a kind of death, decease, expiry
Derived forms verb depart₁, verb depart₄, verb depart₃

departure, n.
1 the act or an instance of departing.
2 (often foll. by from) a deviation (from the truth, a standard, etc.).
3 (often attrib.) the starting of a train, an aircraft, etc. (the departure was late; departure lounge).
4 a new course of action or thought (driving a car is rather a departure for him).
5 Naut. the amount of a ship's change of longitude.

Etymology:
OF departe{uuml}re (as DEPART)

N  avoidance, abstention, abstinence, for bearance, refraining, inaction, neutrality, avoidance, evasion, elusion, seclusion, avolation, flight, escape, retreat, recoil, departure, rejection, shirker, truant, fugitive, refugee, runaway, runagate, maroon, unsought, unattempted, avoiding, neutral, shy of, elusive, evasive, fugitive, runaway, shy, wild, Adj, lest, in order to avoid, Int, forbear!, keep off, hands off!, sauve qui peut!, every man for himself!, devil take the hindmost!, things unattempted yet in prose or rhyme.

N  recession, retirement, withdrawal, retreat, retrocession, departure, recoil, flight, receding, distance oneself from a person.

N  departure, decession, decampment, embarkation, outset, start, removal, exit, exodus, hejira, flight, leave taking, valediction, adieu, farewell, goodbye, auf wiedersehen, sayonara, dosvidanya, ciao, aloha, hasta la vista, stirrup cup, valedictorian, starting point, starting post, point of departure, point of embarkation, place of departure, place of embarkation, port of embarkation, airport, take-off point, taxiing runway, runway, launching pad, spaceport, departing, valedictory, outward bound, whence, hence, thence, with a foot in the stirrup, on the wing, on the move, Int, begone!, farewell!, adieu!, goodbye!, good day!, au revoir!, fare you well!, God bless you!, God speed!, all aboard!, auf wiedersehen!, au plaisir de vous revoir!, bon voyage!, gluckliche Reise!, vive valeque!.

N  death, decease, demise, dissolution, departure, obit, release, rest, quietus, fall, loss, bereavement, mortality, morbidity, end of life &c, cessation of life &c, loss of life, extinction of life, ebb of life, death warrant, death watch, death rattle, death bed, stroke of death, agonies of death, shades of death, valley of death, jaws of death, hand of death, last breath, last gasp, last agonies, dying day, dying breath, dying agonies, chant du cygne, rigor mortis, Stygian shore, King of terrors, King Death, Death, doom, Hell's grim Tyrant, euthanasia, break up of the system, natural death, natural decay, sudden death, violent death, untimely end, watery grave, debt of nature, suffocation, asphyxia, fatal disease, death blow, necrology, bills of mortality, obituary, death song, dead, lifeless, deceased, demised, departed, defunct, extinct, late, gone, no more, exanimate, inanimate, out of the world, taken off, released, departed this life, dead and gone, dead as a doornail, dead as a doorpost, dead as a mutton, dead as a herring, dead as nits, launched into eternity, gone to one's eternal reward, gone to meet one's maker, pushing up daisies, gathered to one's fathers, numbered with the dead, dying, moribund, morient, hippocratic, in articulo, in extremis, in the jaws of death, in the agony of death, going off, aux abois, one one's last legs, on one's death bed, at the point of death, at death's door, at the last gasp, near one's end, given over, booked, with one foot in the grave, tottering on the brink of the grave, stillborn, mortuary, deadly, post obit, post mortem, life ebbs, life fails, life hangs by a thread, one's days are numbered, one's hour is come, one's race is run, one's doom is sealed, Death knocks at the door, Death stares one in the face, the breath is out of the body, the grave closes over one, sic itur ad astra, de mortuis nil nisi bonum, dulce et decorum est pro patria mori, honesta mors turpi vita potior, in adamantine chains shall death be bound, mors ultima linea rerum est, ominia mors aequat, Spake the grisly Terror, the lone couch of this everlasting sleep, nothing is certain but death and taxes.

N  disappearance, evanescence, eclipse, occultation, departure, exit, vanishing point, dissolving views, disappearing, evanescent, missing, lost, lost to sight, lost to view, gone, Int, vanish!, disappear!, avaunt!, get lost!, get out of here.

departure gate, departure lounge, departure tax, departure time, point of departure, time of departure