# Concepts

In this API, some terms are used in specific ways to facilitate understanding and usage. This section clarifies the meanings of these terms.

- **Locker**: A locker represents a location equipped with electronically controlled storage compartments, used by carriers for optimized first-mile and last-mile logistics operations.
- **Module**: Some lockers can be divided into multiple modules, typically done to increase the storage capacity of a locker.
- **Compartment**: Each module features multiple compartments, which come in different sizes.
- **Parcel**: A package that is delivered in and collected from a compartment.