precurse
/prɪˈkɜrs, prɪˈkɜːrs/Definitions
1. verb
to occur or happen before something else, especially something similar or in a similar pattern
“The economic downturn was said to precurse the global financial crisis.”
2. noun
something that happens or occurs before something else
“The precurse to the big storm was a series of strong thunderstorms.”