Definition of "Summit" :
noun: a meeting of heads of governments
noun: the top or extreme point of something (usually a mountain or hill)
"The region is a few molecules wide at the summit."
noun: the highest level or degree attainable; the highest stage of development
"The summit of his ambition."
verb: reach the summit (of a mountain)
"Many mountaineers go up Mt. Everest but not all summit."