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., No definition: (a negative used to express dissent, denial, or refusal, as in response to a question or request).. See examples of NO used in a sentence., As an adverb, adjective, and noun, "no" conveys the meaning of 'not any.' This usage can refer to the complete absence of something, whether it's quantifiable items, presence, or attributes. For example, "No sugar," "No one is here," or "There are no tickets left.", 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., You use no to mean not any or not one person or thing. He had no intention of paying the cash. No job has more influence on the future of the world. No letters survive from this early period., (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.'' (used to emphasize or introduce a negative statement): No, not one of them came..