Bootable media refers to any storage device, such as a USB flash drive or CD/DVD, that contains an operating system or software that can be loaded onto a computer. When a computer is powered on, it can be set to boot from this media instead of the internal hard drive, allowing users to install or repair an operating system. Creating bootable media typically involves using specific software to transfer the necessary files onto the device. This process is essential for tasks like installing a new operating system, running diagnostic tools, or recovering data from a malfunctioning system.