An "app," short for application, is a software program designed to run on a computer or mobile device for a specific purpose. Apps can range from simple tools like calculators and note-taking programs to complex applications like video games, social media platforms, and productivity suites. They are typically downloaded and installed through app stores, like the Apple App Store or Google Play Store, and are designed to be user-friendly and efficient in performing their intended functions. Apps have become ubiquitous in modern life, transforming how we communicate, work, learn, and entertain ourselves.