1) Happening 2) Natural event 3) Occurrence 1) Posteriority 
• (n.) The act of supervening.
Su`per·ven'tion noun [ Latin superventio .] The act of supervening. Bp. Hall. 
supervention 1. To come or to occur as something extraneous, additional, or unexpected. 2. To follow immediately after; to ensue. 3. In philosophy, to be dependent on a set of facts or properties in such a way that change can occur only after change has occurred in those facts or properties. 4. The development of some condition in addition to an...
noun a following on in addition