cross-country skiing

American Heritage® Dictionary of the English Language, Fourth Edition

1. n. The sport of skiing over the countryside rather than on downhill runs.

Wiktionary

1. n. An endurance sport and method of getting about involving travelling on skis, uphill as well as downhill .
2. n. A leisure activity using cross-country skis and ski poles for traversing natural terrain during winter.

WordNet 3.0

1. n. the sport of skiing across the countryside (rather than downhill)