TCP/IP, or Transmission Control Protocol/Internet Protocol, is the fundamental language that all computers on the Internet use to communicate. Human languages are hierarchical – that is, letters are built into words, then words are built into sentences.
Even though TCP/IP is used by computers, it’s built the same way. Bits, the building blocks of all computer data, are organized into words called "packets" that are transmitted from one machine to another on the Internet.
TCP/IP is a universal protocol, meaning that any computer can use it to communicate with any other computer. Data in TCP/IP packets can be sent over many systems, including copper telephone lines, fiber-optic lines, satellite links and hybrid fiber-coaxial cable lines.