The ideal falling motion of something subject only to a gravitational field.
2.
A sudden sharp decrease in some quantity. Synonyms:dip, drop, fall."There was a drop in pressure in the pulmonary artery" , "A dip in prices" , "When that became known the price of their stock went into free fall"
... trip and a faster landing. The UN cruiser cut its engines and dropped like a rock in free fall. Night rain washed the ports and the computer cut in the maximum permissible blast for the minimum time that would reduce their speed to zero at zero altitude. Deceleration sat on their chests and squeezed their bones to rubber. Something crunched heavily ... — The K-Factor • Harry Harrison (AKA Henry Maxwell Dempsey)