TCP/IP, standing for Transmission Control Protocol/Internet Protocol, is a set of communication protocols used for interconnecting network devices on the internet. It’s essentially the fundamental language that defines how data travels across networks.

1. TCP (Transmission Control Protocol): This protocol is responsible for ensuring the reliable transmission of data across the internet. It breaks down large data files into smaller packets for transmission and then reassembles them at the receiving end. TCP also manages flow control and error handling, ensuring that packets are delivered correctly and in order.
2. IP (Internet Protocol): IP handles the addressing and routing of packets, ensuring they reach the correct destination. Each device connected to the internet is assigned a unique IP address. IP routes each packet based on this address.

Together, these protocols enable a variety of internet services like email, web browsing, and file transfer. The robustness and flexibility of TCP/IP have been fundamental to the growth and scalability of the internet. TCP/IP is not only a technical standard but also an amazing example of innovation and collaboration in computer science.