know (someone or something) from (someone or something else)
To be able to distinguish a particular person or thing from someone or something else. Usually used in negative constructions. I've heard his name before, but I wouldn't know him from a stranger on the street. My father is so hopeless when it comes to technology that I'm surprised he knows a mouse from a monitor.
Farlex Dictionary of Idioms. © 2024 Farlex, Inc, all rights reserved.
know someone from someone
to tell the difference between one person and another. I don't knowFred from his twin brother. I know Bill from Bob, but I can't tell most identical twins apart.
know something from something
to tell the difference between one thing and another. (Often with a negative.) You don't know a smoked herring from a squid! She didn't know a raven from a crow, and who does?
know from something
to know about something. (Used on the eastern seaboard.) Do you know from thermostats? You don't know from anything!
McGraw-Hill Dictionary of American Idioms and Phrasal Verbs. © 2002 by The McGraw-Hill Companies, Inc.
know from something
in. to know about something. (see also
not know from nothing.)
Do you know from timers, I mean how timers work? McGraw-Hill's Dictionary of American Slang and Colloquial Expressions Copyright © 2006 by The McGraw-Hill Companies, Inc. All rights reserved.