NO definition: 1. not any; not one; not a: 2. used in signs and on notices to show that something is not allowed…. Learn more. The meaning of NO is not. How to use no in a sentence. No (adverb, noun, adjective) - Used to describe the absence of something when expected or supposed. No is one of the most commonly used words in many languages around the world. You use no to acknowledge a negative statement or to show that you accept and understand it. no是一个多词性的英语单词，主要用作感叹词、限定词、副词、名词和形容词 [4-5]。 作为感叹词或副词时，no用于否定回答、否定陈述、表示惊讶或禁止，例如“Any problems?” — “No, I‘m O.K.”，也可用于纠正之前的话，如“I was twenty-two — no, twenty-one.”。 1. not any, not a, or not one: there's no money left; no card in the file. 2. not by a long way; not at all: she's no youngster. 3. (followed by comparative adjectives and adverbs) not: no fewer than forty men; no more quickly than before. No is the ultimate negative: it means not any, or not at all, and it's also used to express a generally negative response. If there's no milk for your cereal in the morning, there's not a drop left. (used to express dissent, disagreement, denial, or refusal, as in response to a question or request, or in giving a command): Can we leave now?''— No, stay here.'' No is the ultimate negative: it means not any, or not at all, and it's also used to express a generally negative response. If there's no milk for your cereal in the morning, there's not a drop left.