know

verb 1 [with clause ] be aware of through observation, inquiry, or information : most people know that CFCs can damage the ozone layer | I know what I'm doing. • [ trans. ] have knowledge or information concerning : I would write to him if I knew his address [ intrans. ] | I know of one local who shot himself. • be absolutely certain or sure about something : I just knew it was something I wanted to do [ trans. ] | I knew it! 2 [ trans. ] have developed a relationship with (someone) through meeting and spending time with them; be familiar or friendly with : he knew and respected Laura. • have a good command of (a subject or language). • recognize (someone or something) : Isabel couldn't hear the words clearly, but she knew the voice. • be familiar or acquainted with (something) : a little restaurant she knew near Times Square. • have personal experience of (an emotion or situation) : a man who had known better times. • (usu. be known as) regard or perceive as having a specified characteristic : he is also known as an amateur painter. • (usu. be known as) give (someone or something) a particular name or title : the doctor was universally known as “Hubert.” • ( know someone/something from) be able to distinguish one person or thing from (another) : you are convinced you know your own baby from any other in the world. 3 [ trans. ] archaic have sexual intercourse with (someone). [ORIGIN: a Hebraism that has passed into modern languages; compare with German erkennen, French connaître.].