# Glossary

## Activity

Refers to the work carried out by an individual or an organization within a process.
Activities can be classified into three categories: Task, Subprocess, and Call Activity.
These activities can be either atomic or non-atomic.
Atomic activities are indivisible and represent single tasks, while non-atomic activities involve multiple steps or subprocesses that work together to achieve a larger objective.

## Process Instance

A Process Instance is a specific occurrence of a Process Model that is executed within a workflow engine.

## Process Model

A Process Model is a visual representation of a process that defines the sequence of activities, decisions, and interactions required to achieve a particular goal.