ACROSS
3. A person who climbs mountains, a mountain climber → MOUNTAINEER

4. Illness caused by ascent to high altitude, characterized by hyperventilation, nausea, and exhaustion resulting from shortage of oxygen → ALTITUDESICKNESS

5. The pointed top of a mountain → PEAK

6. A camp from which mountaineering expeditions set out → BASECAMP

7. A tool consisting of a shaft, grip, strap, etc., used to reduce the burden on the lower body and maintain balance when climbing→ STICK


DOWN
1. A covering for the hand that has separate parts for each finger → GLOVE

2. A type of flashlight/equipment designed to be worn on the head and fixed to the head → HEADLANTERN

3. A building located at high elevation, in mountainous terrain, generally accessible only on foot, intended to provide food and shelter for mountaineers, climbers and hikers → MOUNTAINHUT

8. A set of outdoor activities that involves ascending mountains → CLIMBING