maximum meaning, definition, what is maximum: the maximum amount, quantity, speed etc.: Learn more. The meaning of MAXIMUM is the greatest quantity or value attainable or attained. MAXIMUM meaning: 1. being the largest amount or number allowed or possible: 2. the largest amount allowed or…. Learn more. 1. the highest amount, value, or degree attained or attainable. 2. an upper limit allowed by law or regulation. If you say that something is a particular amount maximum, you mean that this is the greatest amount it should be or could possibly be, although a smaller amount is acceptable or very possible. MAXIMUM definition: the greatest quantity or amount possible, assignable, allowable, etc. See examples of maximum used in a sentence. The simple definition of MAXIMUM is the highest number or amount that is possible or allowed—usually singular —often + of. MAXIMUM definition: 1. being the largest amount or number allowed or possible: 2. the largest amount allowed or…. Learn more. In mathematical analysis, the maximum and minimum[a] of a function are, respectively, the greatest and least value taken by the function. Both a noun and an adjective, maximum takes it to the max: it means the most, the fastest, the biggest.