unknown

Etymology

From Middle English *unknowen, *uniknowen, uniknowe, from Old English unġecnāwen (“unknown”), equivalent to un- + known.

adj

1. (sometimes postpositive) Not known; unidentified; not well known.
   I suspect that this large and complex military railway system, shrouded in official secrecy for most of its operational life, remains unknown to many people. January 12 2022, Chris Hegg, “The secret railway in the woods”, in RAIL, number 948, page 34

noun

1. (algebra) A variable (usually x, y or z) whose value is to be found.
2. Any thing, place, or situation about which nothing is known; an unknown fact or piece of information.
   Had God walked close beside her into the unknown? 1957, Ethel Erford Hewitt, Into the Unknown: An Historical Novel, page 351
   As we know, There are known knowns. There are things we know we know. We also know There are known unknowns. That is to say We know there are some things We do not know. 2003 [2002], Donald Rumsfeld, edited by Hart Seely, Pieces of Intelligence: The Existential Poetry of Donald H. Rumsfeld
   The other priority is getting people to respond well to interventions, especially changes to routine. This is one of the biggest unknowns in these scenarios, and yet compliance can be the most crucial factor in determining whether an intervention works. 2020-04-09, Ian Boyd, “We practised for a pandemic, but didn’t brace”, in Nature, volume 580, number 7802, page 9
3. A person of no identity; a nonentity
   How does it feel To be on your own With no direction home Like a complete unknown Like a rolling stone? 1965, Bob Dylan, Like a Rolling Stone

verb

1. past participle of unknow