பொருள் : Anything characterized by abrupt and extreme changes (especially up and down).
எடுத்துக்காட்டு :
The economy has been on a roller coaster all year.
பொருள் : Elevated railway in an amusement park (usually with sharp curves and steep inclines).
ஒத்த சொற்கள் : big dipper, chute-the-chute