The provided transcript doesn't explicitly define "API". To understand what an API is, you'll need to consult external resources. However, the video context shows the speaker using "API" in relation to creating a REST API automation framework, implying it's a programmatic interface for interacting with software systems.
This video demonstrates how to generate a REST API automation framework using a prompt-based approach. The speaker uses a prompt to guide an AI tool (implied to be ChatGPT) to create a complete framework, including features like test creation, reporting, and CI/CD integration, minimizing manual coding.