Event = whatever happens (takes place)

Examples:

• My touching my nose now is an event.
• A (particular) leaf falling from a tree is an event.

Event x is causally determined = given what preceded x, x had to occur.

Or, equivalently,

Event x is causally determined = it is causally necessary that (if the events which preceded x occurred, x occurred).

Determinism = the view that all events are causally determined.