TCP/IP is a dual sided acronym that is deciphered into Transmission-Control-Protocol / Internet Protocol.
Transmission Control Protocol is a set of instructions/system of rules that deals with packet ordering and other communication level errors that relate to the internet.
Internet Protocol is the base layer communication system that is standard in the greater worldwide internet.
These two protocols are commonly addressed at one time becase they rely on one another to properly allow for communication to take place over the internet. IP take care of the processes that are related to the message origin, transportation, and destination, while TCP takes care of proper message assemblage.