Quantity  n. (pl. -ies) 1 property of things that is measurable. 2 size, extent, weight, amount, or number. 3 specified or considerable portion, number, or amount (buys in quantity; small quantity of food). 4 (in pl.) Large amounts or numbers; an abundance. 5 length or shortness of vowel sounds or syllables. 6 math. Value, component, etc. That may be expressed in numbers. [latin quantus how much]