DictionaryAI

known

SayNOHN/noʊn/UK/nəʊn/

Adjectivebetter known, best known

Noun pluralknowns

4 meanings of known

Practice

  1. 1
    after haveverb
    Past participle of know.

    She has known the truth all along.

    This recipe has been known to families here for generations.

    UsageUse after have or be: has known, is known (not incorrect: has knew). Knew stands alone: she knew.

    Note

    One archaic, euphemistic use of the verb survives mainly in a fixed phrase: to have known someone "in the biblical sense" means to have had sexual relations with them.

  2. 2
    adjective
    That people know about or have identified; recognized, familiar or already established ('a known risk'; 'the oldest known example').

    Scientists compared the new readings against known values from earlier studies.

    The treatment relies on known principles of chemistry.

    UsageKnown to names the people who know: known to few scientists. Often after well, widely or little: a widely known fact.

    Oppositeunknown

    Note

    The word covers both established knowledge (a known risk) and a settled identity or reputation (a known criminal), and it works after a verb as well as before a noun: the reason plaque forms "isn't entirely known."

  3. 3
    nouncountable
    In general use rather than mathematics, a fact or situation that is already understood or familiar.

    Treat the budget as a known and plan everything else around it.

    A solid forecast rests on a few reliable knowns.

    UsageUsually plural and paired with its opposite: the knowns and unknowns of a plan.

    Similargiven, certainty, fact

    Oppositeuncertainty

    Note

    The adjective is also used as a countable noun for an established fact or circumstance. It often appears in the plural alongside unknowns, especially in planning and research.

Less common meaning

  1. 4
    given (math)nouncountable
    A constant or variable whose value is already determined.

    Each known in the system reduces the number of equations you need.

    Rearrange the equation to express the unknown in terms of the knowns.

    Oppositeunknown

    Note

    In algebra the word names a role, not a kind of symbol. A known is any quantity fixed before you begin, whether a constant or a variable whose value has been given, and the unknowns are what you solve for. The working habit is to rearrange an equation so that each unknown is expressed in terms of the knowns, and every value supplied in advance is one less unknown to solve for.

    Checked 5 Nov 2026 · 1 fact

    • Additional known information may be redundant, so it does not automatically reduce the number of equations needed. Independent constraints, rather than the number of known quantities, determine whether unknowns can be found. en.wikipedia.org

known is a form of know

know, verb: To have information about something in your mind, to be aware that it is true, or to be informed of or about it. Full entry

Forms
knowknows he/she/itknowing -ing formknew past tenseknown past participle
Spelling
know → known: irregular (no -ed)

Practice

Can you tell the meanings of known apart? Answer 4 quick questions from this page, or write your own sentence and AI will check it.

Origin

The past participle of "know," from Middle English knowen and Old English cnāwen, formed from "know" plus the ending "-n."

Checked 5 Nov 2026 · 3 facts