verb (used with object), knew, known, know·ing.
- to perceive or understand as fact or truth; to apprehend clearly and with certainty: I know the situation fully.
- to have established or fixed in the mind or memory: to know a poem by heart; Do you know the way to the park from here?
- to be cognizant or aware of: I know it.
- be acquainted with (a thing, place, person, etc.), as by sight, experience, or report: to know the mayor.
- to understand from experience or attainment (usually followed by how before an infinitive): to know how to make gingerbread.
- to be able to distinguish, as one from another: to know right from wrong.
- Archaic. to have sexual intercourse with.
verb (used without object), knew, known, know·ing.
- to have knowledge or clear and certain perception, as of fact or truth.
- to be cognizant or aware, as of some fact, circumstance, or occurrence; have information, as about something.
- the fact or state of knowing; knowledge.
- in the know, possessing inside, secret, or special information.
- know the ropes, Informal. to understand or be familiar with the particulars of a subject or business: He knew the ropes better than anyone else in politics.
verb knows, knowing, knew (njuː) or known (nəʊn) (mainly tr)
- (also intr; may take a clause as object) to be or feel certain of the truth or accuracy of (a fact, etc)
- to be acquainted or familiar withshe’s known him five years
- to have a familiarity or grasp of, as through study or experiencehe knows French
- (also intr; may take a clause as object) to understand, be aware of, or perceive (facts, etc)he knows the answer now
- (foll by how) to be sure or aware of (how to be or do something)
- to experience, esp deeplyto know poverty
- to be intelligent, informed, or sensible enough (to do something)she knew not to go home yet
- (may take a clause as object) to be able to distinguish or discriminate
- archaic to have sexual intercourse with
- I know what I have an idea
- know what’s what to know how one thing or things in general work
- you know informal a parenthetical filler phrase used to make a pause in speaking or add slight emphasis to a statement
- you never know things are uncertain
- in the know informal aware or informed
Old English cnawan (class VII strong verb; past tense cneow, past participle cnawen), “to know, perceive; acknowledge, declare,” from Proto-Germanic *knew- (cf. Old High German bi-chnaan, ir-chnaan “to know”), from PIE root *gno- “to know” (cf. Old Persian xšnasatiy “he shall know;” Old Church Slavonic znati, Russian znat “to know;” Latin gnoscere; Greek *gno-, as in gignoskein; Sanskrit jna- “know”). Once widespread in Germanic, this form is now retained only in English, where however it has widespread application, covering meanings that require two or more verbs in other languages (e.g. German wissen, kennen, erkennen and in part können; French connaître, savoir; Latin novisse, cognoscere; Old Church Slavonic znaja, vemi). The Anglo-Saxons used two distinct words for this, witan (see wit) and cnawan.
Meaning “to have sexual intercourse with” is attested from c.1200, from the Old Testament. To not know one’s ass from one’s elbow is from 1930. To know better “to have learned from experience” is from 1704. You know as a parenthetical filler is from 1712, but it has roots in 14c. To know too much (to be allowed to live, escape, etc.) is from 1872. As an expression of surprise, what do you know attested by 1914.
“inside information” (as in in the know), 1883; earlier “fact of knowing” (1590s), from know (v.).
In addition to the idioms beginning with know
- know all the answers
- know a thing or two
- know beans
- know better
- know by heart
- know by sight
- know enough to come in out of the rain
- know from Adam
- know if one is coming or going
- know it all
- know like a book
- know one’s own mind
- know one’s place
- know one’s stuff
- know one’s way around
- know only too well
- know the ropes
- know the score
- know where one stands
- know which side of one’s bread is buttered
- before you know it
- (know) by heart
- come in out of the rain, know enough to
- coming or going, know if one’s
- for all (I know)
- god knows
- (know) inside out
- in the know
- it takes one to know one
- left hand doesn’t know what right hand is doing
- not know beans
- not know from Adam
- not know where to turn
- not know which way to jump
- thing or two, know
- what do you know
- what have you (who knows what)
- which is which, know
- you know