K2
The mountain range that begins with A and is four letters long is the Alps.
Adirondacks
so
Peak
ibex
mountain
tarn (a mountain lake).
ural
Pisses
A gorilla with nine letters is "mountain." Mountain gorillas are a subspecies of the Eastern gorilla, found in the mountainous regions of central Africa. They are known for their distinctive thick fur and are critically endangered due to habitat loss and poaching.
Ida. http://en.wikipedia.org/wiki/Mount_Ida
Looks like "communication." (the letters can also spell comic mountain)