Dozen's another word for the number twelve. The dozen may be one of the earliest primitive groupings, perhaps because there're approximately a dozen cycles of the moon or months in a cycle of the sun or year. The dozen's convenient because its multiples and divisors are convenient: 12 = 2 × 2 × 3, 3 × 4 = 2 × 6, 60 = 12 × 5, 360 = 12 × 30. The use of twelve as a base number, known as the duodecimal system (also as dozenal), probably originated in Mesopotamia (… (More on Dozen)