quinary

Quinary refers to the number five or to numeral systems built on base five. The term derives from Latin quintarius, meaning “of five.” In mathematics, quinary denotes a positional numeral system in which each digit represents a coefficient for successive powers of five, analogous to decimal (base 10) or binary (base 2). The permitted digits are 0 through 4. For example, the decimal number 86 converts to 321 in base-5, since 3×25 + 2×5 + 1 = 86. Conversely, 321_5 equals 86_10.

Quinary systems have limited use in contemporary computing and everyday commerce, where base-10 and base-2 prevail. They appear primarily in historical counting methods and in the study of numeral families as linguistic or anthropological curiosities. Some languages and cultures organize counts around the number five, sometimes combining quinary with other bases in mixed-radix systems.

Beyond purely numerical use, the adjective quinary can describe things arranged in fives, such as five-part structures or fivefold classifications. In practice, quinary is of interest mainly to number theory, historical linguistics, and the study of numeral systems rather than as a practical encoding for modern information processing.