Occurrence
Incident
Synonyms: Event, happening, affair, experience, development, eventuality, incident, phenomenon, matter, circumstance, and contingency.
Existence
Synonyms: Existence, appearance, materialization, springing up, incidence, prevalence, instance, manifestation, development, frequency, rate, and distribution.
Example Sentences
The rare occurrence surprised everyone present.
Flooding is a common occurrence here.
This strange occurrence remains unexplained.
It was an unexpected occurrence during dinner.