Atlas is a data mapper implementation for persistence models (not domain models).
As such, Atlas uses the term "record" to indicate that its objects are not domain objects. Use Atlas records directly for simple data source interactions at first. As a domain model grows within the application, use Atlas records to populate domain objects. (Note that an Atlas record is a "passive" record, not an active record. It is disconnected from the database.)
Documentation is at http://atlasphp.io.