Mountainside (noun)

1. The side of a mountain.
2. A slope of a mountain, especially one that is steep or rugged.

Origin:

A combination of the words "mountain" and "side".

Examples:

1. The mountain trail was steep and treacherous as it wound its way up the mountainside.
2. The view from the top of the mountainside was breathtaking.
3. The mountainside was covered in snow and ice.
4. The mountainside was dotted with wildflowers.
5. He climbed the mountainside to reach the summit.