Discrete System
Changes that happen in specific moments in between which the system remains unchanged
Continuous System
Changes happening constantly without a specific even e.g. the temperature in a room
Dynamic Objects
Move through thr system and interact with other entities
Passive Entity
Does not make any decision or creates actions
Event
One occurrance that changes the state of a system
Activity
A task during a duration of time
Attributes
Characteristics that every entity in a system has