/swich"bak'/ , n.
1. a highway, as in a mountainous area, having many hairpin curves.
2. Railroads. a zigzag track arrangement for climbing a steep grade.
3. Brit. See roller coaster .
v.i.
4. (of a road, railroad track, etc.) to progress through a series of hairpin curves; zigzag: The road switchbacks up the mountain.
[ 1860-65, Amer.; SWITCH + BACK 2 ]