occurrence vs one-off

Other hyponyms of occurrence include accompaniment, attendant, co-occurrence, concomitant, avalanche, experience, trouble, treat, miracle, marvel, wonder, thing, episode, contingence, contingency, eventuality, beginning, conclusion, ending, finish, periodic event, recurrent event, alteration, change, modification, computer error, error, accident, chance event, fortuity, stroke, fire, incident, discharge, case, example, instance, motion, movement, failure, success, appearance, destiny, fate, disappearance, disappearance, contact, impinging, striking, finish, collapse, break, interruption, sound, union, news event, flash, convergence, juncture, occasion, burst, flare-up, outburst, eruption, irruption, outbreak, black eye, blow, reversal, reverse, setback, bonanza, boom, bunce, godsend, gold rush, gravy, manna from heaven, windfall, collapse, crash, supervention.