Five

Five is the natural number that follows four and precedes six. It is written as 5 in most modern notation and as V in Roman numerals. The English word five derives from Old English fif, related to other Germanic forms, and ultimately from the Proto-Indo-European root penk- meaning “five.” The prefix pent- in words such as pentagon and pentathlon also stems from the Greek pente, meaning five.

In mathematics, five is a prime number, with only 1 and itself as divisors. It is the third prime and is also a pentagonal number, appearing as 5 in the sequence of pentagonal numbers. In common numeral bases, five is represented as 5 in decimal, 101 in binary, and 5 in hexadecimal. The symbol V for five in Roman numerals reflects an early form of the tally system.

Five appears in many cultural and practical contexts. Humans typically have five senses and five fingers on a hand, contributing to the prominence of the number in everyday life. Classical traditions often speak of five elements (such as earth, water, air, fire, and aether) and of pentagonal or pentagram shapes in art and symbolism. The vowel system in many languages is organized around five letters, and well-known constructs include the Five Pillars of Islam and the five Olympic rings, which symbolize unity among five inhabited continents. In geography, the “Five Boroughs” of New York City is a common reference.