A removable disk refers to an external storage medium that can be easily removed or detached from the device it is connected to. Other synonyms for the term 'removable disk' include portable drive, external hard disk, USB drive, flash drive, memory stick, and thumb drive. These devices are very useful and come in handy for transferring files and data from one device to another. They usually have a large storage capacity, making them ideal for storing large files such as videos and high-quality images. The popularity and usefulness of removable disks have made them a crucial component of modern-day computing and storage systems.