Which attribute defines the source URL of an image?

The attribute that defines the source URL of an image is "src." In HTML, the "src" attribute is used within the tag to specify the path to the image file that should be displayed on a webpage. This URL can point to an image stored locally on the server or a remote image hosted elsewhere on the internet.

Understanding how to correctly use the "src" attribute is crucial for web development, as it directly affects the content being rendered on the webpage. An image will not appear if the "src" attribute is omitted or incorrectly defined.