free_fall
1. [ noun ] a sudden sharp decrease in some quantity
Synonyms: drop dip fall
Examples:

"a drop of 57 points on the Dow Jones index" "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"

Related terms: decrease voltage_drop correction decrease
2. [ noun ] the ideal falling motion of something subject only to a gravitational field
Related terms: drop