Non-operating revenue refers to income generated by a company from activities not related to its core business operations. This can include earnings from investments, interest income, or gains from the sale of assets. For example, if a company sells a piece of real estate it no longer needs, the profit from that sale would be considered non-operating revenue. This type of revenue is important for understanding a company's overall financial health, as it can provide additional funds that support operations or growth. However, it is typically less predictable than operating revenue, which comes from regular business activities like selling products or services.