A computer program is a set of instructions that tells a computer how to perform specific tasks. These instructions are written in programming languages, such as Python, Java, or C++. Programs can range from simple applications, like a calculator, to complex systems, like operating systems or video games. Computer programs are executed by a computer's processor, which interprets the instructions and carries out the tasks. They can be used for various purposes, including data processing, automation, and entertainment. Programs can be created for personal use or distributed to a wider audience through software applications.