Greatest in quantity or highest in degree attainable or attained; as, a maximum consumption of fuel; maximum pressure; maximum heat.
source: Webster 1913
noun
the largest possible quantity
source: WordNet 3.0
the greatest possible degree
He tried his utmost.
source: WordNet 3.0
the point on a curve where the tangent changes from positive on the left to negative on the right
source: WordNet 3.0
The greatest quantity or value attainable in a given case; or, the greatest value attained by a quantity which first increases and then begins to decrease; the highest point or degree; -- opposed to minimum.