switchback

UK: /ˈswɪtʃbæk/ US: (swich′bak′)

WordReference Random House Unabridged Dictionary of American English © 2025

switch•back  (swich′bak′), n. 

1. Transport a highway, as in a mountainous area, having many hairpin curves.
2. Rail Transport a zigzag track arrangement for climbing a steep grade.
3. British Terms See roller coaster. 

v.i. 

4. Rail Transport, Transport (of a road, railroad track, etc.) to progress through a series of hairpin curves;
   zigzag:
   The road switchbacks up the mountain.

• switch + back² 1860–65, American.

Collins Concise English Dictionary © HarperCollins Publishers::

switchback / ˈswɪtʃˌbæk/ noun

1. a mountain road, railway, or track which rises and falls sharply many times or a sharp rise and fall on such a road, railway, or track
2. another word (esp Brit) for big dipper