A logical operator that returns a false value if the operand is true and a true value if the operand is false.
not(nt)
adv.
In no way; to no degree. Used to express negation, denial, refusal, or prohibition: I will not go. You may not have any.
[Middle English, alteration of naught, nought; see naught.]
Usage Note: Care should be taken with the placement of not and other negatives in a sentence in order to avoid ambiguity. All elephants are not friendly could be taken to mean either All elephants are unfriendly or Not all elephants are friendly. Similarly, the sentence Kim didnt sleep until noon could mean either Kim went to sleep at noon or Kim got up before noon. · In formal writing, each part of the not only . . . but also construction should be followed with an element of the same grammatical type. Instead of She not only bought a new car but also a new lawnmower, one should write She bought not only a new car but also a new lawnmower; in the second version, both not only and but also are followed by noun phrases. Omitting the also tends to intensify the second part of the construction so that it no longer functions merely as a supplement to the first part: She is not only smart but brilliant. He not only wanted the diamond but wanted it desperately. See Usage Note at only.
not /nt/ adv.1 used to express negation, refusal, or denial, often shortened to nt after auxiliary verbs: He will not pay his bill.||You shouldnt say that.||Are you ready? No, Im not.||Dont leave yet.||She doesnt believe that hes guilty. (= She believes that he isnt guilty.)2not at all: a response to an expression of gratitude: I really appreciate your help. Not at all, it was no trouble.3 conj.not that: used to begin a phrase expressing negation: He said he was sorry not that it matters.