Definition of "roller coaster" [roller coaster]

• A steep, sharply curving elevated railway with small open passenger cars that is operated at high speeds as a ride, especially in an amusement park. (noun)
• An action, event, or experience marked by abrupt, extreme changes in circumstance, quality, or behavior: "the demographic roller coaster caused by the baby boom” ( American Demographics). (noun)

American Heritage(R) Dictionary of the English Language, Fifth Edition. Copyright (c) 2011 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.

• "Groupies, with their flashy selves and wide-eyed willingness to please, were like the perfect theme park roller coaster where the lines were short and the rides were free."
• "It was a daily roller coaster of emotionsfrom fear to frustration to exhilaration or despair, depending on how my practice or performance went."
• "Her rheumatologist worried about the ramifications of having her on a roller coaster of prednisone and decided to try Imuran, a chemotherapy medication that suppresses the immune system in general, which he and Joy had been hoping to avoid since it carries with it a heightened risk of lymphoma and leukemia."