unknown
uh-nohn
Unknown (adjective) means not known, identified, or familiar. Example: “The cause of the fire is still unknown.”
adjective
1
Not known, identified, or familiar.
"The cause of the fire is still unknown."
"An unknown singer opened the concert."
"A parcel from an unknown sender was left outside our front door."
noun
1
A variable, typically x, y, or z, whose value must be worked out.
"Solve the equation for the unknown."
"In this problem, x is the unknown, and you must find its value."
"If you know the total and one number, you can find the unknown."
2
Something not yet known or understood.
"Many people fear the unknown more than any real danger."
"Starting a new job in a new city means stepping into the unknown."
"Scientists spend their careers exploring the unknown, one small question at a time."
How to use unknown
Learner’s notesIn plain EnglishNot identified or not yet found out — as an adjective describing a fact, or a noun for the thing itself.
Common pairings
unknown cause
venture into the unknown
solve for the unknown
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Word forms
- Plural
- unknowns
- Comparative
- more unknown
- Superlative
- most unknown
Fill the gap
Can you complete this real example?
The cause of the fire is still _____.
Etymology
From Old English ungecnawen, from "un-" + "known."
Synonyms
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unfamiliar
unidentified
undiscovered
obscure
mysterious
nameless
uncharted
alien
stranger
unknown region
terra incognita
unknown quantity
Antonyms
Related words
Frequently asked questions
What does “unknown” mean?
The word “unknown” means not known, identified, or familiar. In plain terms, not identified or not yet found out — as an adjective describing a fact, or a noun for the thing itself.
How do you pronounce “unknown”?
“Unknown” is pronounced uh-nohn (/ʌnˈnoʊn/ in IPA).
How do you use “unknown” in a sentence?
Here is “unknown” used in a sentence: “The cause of the fire is still unknown.”
What is the opposite of “unknown”?
The opposite of “unknown” — its antonyms — are ascertained, familiar, famous, known and recognizable.
What part of speech is “unknown”?
Depending on how it is used, “unknown” can be an adjective and a noun.
Where does the word “unknown” come from?
The word “unknown” comes from Old English. From Old English ungecnawen, from "un-" + "known.".
Is “unknown” a common word?
“Unknown” is a fairly common word in modern English, usually learned at around the A2 level.
How many meanings does “unknown” have?
“Unknown” has 3 distinct senses listed in this dictionary. The most common is: not known, identified, or familiar.
What is the difference between unknown and anonymous?
Unknown means not known, identified, or familiar in a general sense, applying to facts, places, or people. Anonymous specifically means a name is deliberately withheld or unavailable, as with an anonymous donor. Something can be unknown simply because no one has discovered it, while anonymous implies an identity exists but is hidden.
What is the opposite of unknown?
The main opposites are 'known,' 'familiar,' and 'identified.' Depending on context, you might also use 'famous' or 'renowned' when contrasting an unknown person with a celebrity. The right opposite depends on whether you mean something not yet discovered, not recognised, or simply not well known to the public.
What does 'the unknown' mean as a noun?
As a noun, 'the unknown' refers to everything that has not been discovered, understood, or experienced, often carrying a sense of mystery or uncertainty. People speak of 'fear of the unknown' when they feel anxious about what lies ahead. In maths, an unknown is also a value you are trying to find.
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