Name for HTTP Request+Response

Question

There's one thing I haven't found in rfc 2616 and that's a "canonical" name for a request/response pair. Is there such thing?

  4.1 Message Types

    HTTP messages consist of requests from client to server and responses
    from server to client.

       HTTP-message   = Request | Response     ; HTTP/1.1 messages

Taking this as a template, which word would you put in the following sentence?

  A single complete HTTP ... consists of one HTTP Request and one HTTP Response

       HTTP-... = Request Response 

roundtrip? cycle?

Answer 1

Transaction, yes, or "A singe HTTP Request consists of one HTTP Request message and one HTTP Response message."

Answer 2

The spec calls them "exchanges" (or "request/response exchanges"),

In HTTP/1.0, most implementations used a new connection for each
request/response exchange. In HTTP/1.1, a connection may be used for one or more request/response exchanges.