Definition of CONCURSUS. : the influx of divine causation upon secondary causes; especially: the doctrine that before the fall man was preserved from sin by the aid of God.ADVERTISEMENT. Medieval Latin, from Latin, concourse — more at concourse.rigin of CONCURSUS. Medieval Latin, from Latin, concourse — more at concourse. This word doesn't usually appear in our free dictionary, but the definition from our premium Unabridged Dictionary is offered here on a limited basis.