A USB drive, also known as a flash drive or thumb drive, is a small, portable storage device that connects to computers and other devices via a USB (Universal Serial Bus) port. It is used to store and transfer data, such as documents, photos, and videos, making it a convenient tool for both personal and professional use. USB drives come in various storage capacities, ranging from a few megabytes to several terabytes. They are durable and can easily fit in a pocket or on a keychain, allowing users to carry important files with them wherever they go.