1. a small gravity railroad, esp. in an amusement park, having a train with open cars that moves along a high, sharply winding trestle built with steep inclines that produce sudden, speedy plunges for thrill-seeking passengers.
2. a car or train of cars for such a railroad.
3. any phenomenon, period, or experience of persistent or violent ups and downs, as one fluctuating between prosperity and recession or elation and despair.
Pronunciation: (rō'lur-kō"stur, rō'li-),[key] —v.i. 1. to go up and down like a roller coaster; rise and fall: a narrow road roller-coastering around the mountain; a light boat roller-coastering over the waves. 2. to experience a period of prosperity, happiness, security, or the like, followed by a contrasting period of economic depression, despair, or the like: The economy was roller-coastering throughout most of the decade.
—adj. 1. of, pertaining to, or characteristic of a roller coaster.
2. resembling the progress of a ride on a roller coaster in sudden extreme changeableness.