Unknown

How to spell unknown

7 letters · 2 syllables

How to pronounce unknown

Say the part in capitals loudest.

What does unknown mean?

1. adjectiveNot known, recognised, or identified.

Unknown in a sentence

• The cause of the fault remains unknown to the engineers.

• The package arrived from an unknown sender.

Where does unknown come from?

Language of origin: Germanic

This word is built from native Old English elements rather than borrowed ones. The prefix 'un-' is the Germanic negator meaning simply 'not', and 'known' is the past participle of the verb 'know', from Old English 'cnawan', which meant 'to recognise or be acquainted with'. That verb traces back through Proto-Germanic to an ancient Indo-European root 'gno-', meaning 'to know', the same root that surfaces in Latin 'noscere' and Greek 'gignoskein' and feeds English words like 'recognise' and 'diagnosis'. The silent 'k' in 'know' and therefore in 'unknown' is a fossil of older pronunciation, when the 'k' was actually sounded before a following 'n'; English stopped pronouncing it around the seventeenth century but kept the letter in the spelling. The combined form 'unknown' has been in steady use since the medieval period to describe whatever lies outside our awareness.

How the word is built

• un- (not)
• know (to be aware of)
• -n (past participle suffix forming an adjective)