What does «prevenir» mean in Spanish?

Prepare, arrange in advance.
Precaution, avoidance.

Examples of use in Spanish: "prevenir una enfermedad".
To foresee, to know in advance.

Examples of use in Spanish: "prevenir una objeción"; "prevenir una dificultad".
To warn, inform, advise.

Examples of use in Spanish: "prevenir a la autoridad de un peligro público".