What is Ancillary Revenue?

Legal Definition
In the airline industry, ancillary revenue is revenue from non-ticket sources, such as baggage fees and on-board food and services, and has become an important financial component for low-cost carriers (LCCs) in Europe, North America and other global regions. Ancillary revenue has been defined as, “Revenue beyond the sale of tickets that are generated by direct sales to passengers, or indirectly as a part of the travel experience.” Ancillary revenue has been further defined to include these categories: à la carte features, commission-based products, and frequent flier activities.
-- Wikipedia
Legal Definition
Profits gotten from nonprimary products offered.