verb
occur
uh-KUR/əˈkɜːr/
To take place.
A lightning strike occurs, breaking a branch from the tree.

Etymology
“Running toward” people gives the image of meeting them. The meaning shifted from “meet” to “present itself” and then to “happen”: an event presents itself in the course of affairs.
In context
notifications to Government under the HIIAT procedure happen when two or more linked cases of infection occur
More examples
- The accident occurred just before sunrise.
- Power outages are occurring more often this summer.
- If an error occurs, restart the program.
Forms
occur · occurs · occurred · occurring
occurrence noun — An event or instance of something happening.