From WordNet (r) 3.0 (2006) [wn]:
col
n 1: a pass between mountain peaks [syn: col, gap]
From The Collaborative International Dictionary of English v.0.48 [gcide]:
Col- \Col-\
A prefix signifying with, together. See Com-.
[1913 Webster]
From The Collaborative International Dictionary of English v.0.48 [gcide]:
Col \Col\, n. [F., neck, fr. L. collum neck.]
A short ridge connecting two higher elevations or mountains;
the pass over such a ridge.
[1913 Webster]