The term 'circular object' can be described by two crossword solutions: DISK (4 letters) and WHEEL (5 letters). A DISK is a flat, round object that is usually made of metal, plastic, or paper. It is often used to store data or information, such as a computer hard drive. A WHEEL is a circular object that is usually made of metal or rubber and is used for transportation, such as the wheels on a car. Both disks and wheels are examples of circular objects.