Force is a fictitious force that some people believe causes you to feel as if you are being pushed outward from the center of a circle while traveling in uniform circular motion.

The complete sentence is:
Centrifugal force is a fictitious force that some people believe causes you to feel as if you are being pushed outward from the center of a circle while traveling in uniform circular motion.

In fact, centrifugal force is an inertial force: it is not a real force, but it is due to the fact that the reference frame is rotating. The real force in a uniform circular motion is the centripetal force, which pushes towards the centre of the circle, and keeps the object in circular motion.

This is what a calorimeter is used for simpler ex, to measure calories in food.