Entities are the data sent with an HTTP message:
An entity is better known as the body or in a network context, this is the payload of the message.
The entity of an HTTP message can have an arbitrary data format, which is usually specified as a MIME type in a header field. Accept → text/css,*/*;q=0.1 ?
A response can contain:
Or a request can include the parameters that you entered into a web form.
See the content-disposition header