TCP/IP, which stands for Transmission Control Protocol/Internet Protocol, is the fundamental communication language or protocol used for the Internet. It is a suite of communication protocols that enables different types of computers and networks to communicate with each other. TCP/IP is responsible for ensuring that data is sent and received accurately and efficiently across the network.

The suite consists of two main protocols:

1. **Transmission Control Protocol (TCP):** This protocol is responsible for breaking down data into smaller packets before they are sent over the network and then reassembling them in the correct order at the destination. TCP ensures reliable and error-checked delivery of data between applications running on hosts communicating via an IP network. It manages the flow of data to prevent congestion and ensures that packets are delivered in the correct sequence.

2. **Internet Protocol (IP):** This protocol is responsible for addressing and routing the packets of data so that they can travel across networks and arrive at the correct destination. IP assigns unique addresses to each device on the network, known as IP addresses, which are used to identify the source and destination of data packets. It handles the forwarding of packets from one router to another until they reach their final destination.

Together, TCP/IP provides the foundation for data exchange on the Internet, supporting a wide range of applications and services, such as web browsing, email, file transfer, and more. It is designed to be robust, scalable, and flexible, allowing it to support the vast and ever-growing global network that is the Internet.