What does the prefix uni- mean?
Uni- comes from the Latin unus, which means "one". It shows singularity or unity.
ESEN
Prefix · quantity · one
uni-
Means "one" or "single": uniform, unique, universe, unity, unicorn, unify.
Basic
Written by Bryan López, English teacher · Updated
Uni- or mono-: two ways to say one
Both mean "one", but uni- comes from Latin and mono- from Greek. Uni- stays in words that work as a single unit: something with one horn, one wheel or one shape. Mono- is used more in science and linguistics. If you see uni-, think of something that joins together or stays as one.
How it is used
Attaches to nouns and adjectives to mean "one" or "single":
- uni- + noun/adjectiveform → uniformcycle → unicyclecorn → unicornverse → universelateral → unilateral
- derived formsfy → unifyty → unityson → unisonque → uniqueon → union
Pronunciation: /juːnɪ/. Do not confuse with mono- (Greek origin, more scientific): unicycle vs. monorail.
How it is pronounced
uni-/juːnɪ/
Tap the button to hear how the prefix sounds. Each word in the table has its own audio.
Examples
Root word
With uni-
In a phrase
- formuniformAll students wear a uniform to school every day.
- queuniqueHer voice is so unique that everyone recognises her immediately.
- verseuniverseThe universe contains billions of galaxies and countless stars.
- tyunityThe team's unity carried them to victory in the final.
- cornunicornA unicorn is a mythical creature with a single horn.
- fyunifyThe anthem helped unify the crowd into one voice.
- cycleunicycleShe learned to ride a unicycle in just one week.
Common mistakes
uni- and mono- are interchangeable
uni- is Latin (formal/everyday vocabulary); mono- is Greek (scientific/technical vocabulary) — the word's origin determines which prefix it takes
"Uni-" and "mono-" both mean "one" but are not freely interchangeable. "Uniform" is not "monoform." "Monologue" is not "unilogue." The historical root of the word determines the prefix: words of Latin origin take uni-; words of Greek origin take mono-. When in doubt, uni- is the safe choice for everyday words.
A trick to remember it
Think of a uniform, one single look for everyone: uni- = one, unique. unique, universe.
Practise what you learned
Exercise 1 · Form the word
Exercise 2 · Pick the right one
What is the difference between "uni-" and "mono-"?
Frequently asked questions
What does the prefix uni- mean in English?
The prefix uni- means "one" or "single": uniform, unique, universe, unity, unicorn, unify.
How do you pronounce uni-?
The prefix uni- is pronounced /juːnɪ/. For example, "uniform".
Can you give an example of a word with uni-?
"form" becomes "uniform". It is a typical example of the uni- prefix.
Other useful prefixes
bi-
Signals two or double: bicycle, bilingual, bilateral, bifocal, biannual.
mono-
Signals one or uniqueness: monologue, monopoly, monotone, monochrome, monolingual.
multi-
Signals many or multiple: multiply, multicultural, multimedia, multitask, multilingual.
tri-
Signals three: triangle, trilogy, tricycle, triathlon, tripod, trimester.
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