Math > Numbers

Numerical Prefixes

A prefix is a syllable at the beginning of a word. A numerical prefix lets you know how many there are of a particular thing. Here are some common numerical prefixes.

Prefix	Prefix meaning	Sample words
uni-	1	unicorn: mythical creature with one horn
mono-	1	monorail: train that runs on one track
bi-	2	bicycle: two-wheeled vehicle
tri-	3	triceratops: three-horned dinosaur
quadr-	4	quadruped: four-footed animal
quint-	5	quintuplets: five babies born at a single birth
penta-	5	pentagon: figure with five sides
hex-	6	hexapod: having six legs, an insect, for example
sex-	6	sextet: group of six musicians
hept-	7	heptathlon: athletic contest with seven events
sept-	7	septuplets: seven babies at a single birth
octo-	8	octopus: sea creature with eight arms
novem-	9	novena: prayers said over nine days
deka- or deca-	10	decade: a period of 10 years
cent-	hundred	century: a period of 100 years
hecto-	hundred	hectogram: 100 grams
milli-	thousand	millennium: a period of 1,000 years
kilo-	thousand	kilogram: 1,000 grams
mega-	million	megaton: one million tons
giga-	billion	gigawatt: one billion watts