Definition: Copilot

An AI chatbot developed by Microsoft. Copilot uses language models from Microsoft, Anthropic and OpenAI (Microsoft owns approximately 25% of OpenAI, having committed more than $10 billion in funding as of 2026).

In February 2023, Copilot was integrated into the company's Bing search engine as the "New Bing" and "Bing Chat." Shortly thereafter, Microsoft 365 Copilot was announced, which added AI capability to its flagship office suite. In September, the brand was consolidated into Microsoft Copilot and the Bing references were dropped.

In early 2024, Microsoft launched Copilot Pro, a paid version with more features; however, it was discontinued in 2025.

Microsoft 365 Falls Under Copilot
Not only did Copilot replace the earlier Cortana virtual assistant, but it made a major transformation. Instead of its original side panel option for users, Copilot became the interface that Microsoft 365 apps run under. See Cortana, Bing Chat and Bing.

Copilot Key

To encourage people to use Copilot, Microsoft began promoting keyboards with a dedicated Copilot key like this. (Image courtesy of Microsoft.)