host-to-host
Click on the red underlined text to get to the source
... Transmission Control Protocol (TCP) is intended for use as a highly
reliable host-to-host protocol between hosts in packet-switched computer
communication networks ...
... service in a multinetwork environment. The TCP is
intended to be a host-to-host protocol in common use in multiple
networks.
...
... Transmission Control Protocol: A host-to-host protocol for
reliable communication in internetwork environments. ...