Numerical Prefixes
Updated February 21, 2017 | Factmonster Staff 
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 | |
