A smartphone is a portable electronic device that combines the functions of a mobile phone and a computer. It allows users to make calls, send messages, and access the internet. Smartphones typically have a touchscreen interface and can run various applications, or apps, for tasks like social media, navigation, and gaming. Most smartphones are equipped with cameras, enabling users to take photos and videos. They also include features like GPS for location tracking and sensors for health monitoring. Popular brands of smartphones include Apple, Samsung, and Google, each offering different models with unique features and specifications.