tell things apart

tell (someone or something) apart

To be able to discern or distinguish two or more people or things that appear or seem similar. This one is real, and this one is the counterfeit—you can tell them apart by the small holographic mark at the top corner of the genuine document. Even our parents sometimes have trouble telling me and my brother apart.
See also: apart, tell
Farlex Dictionary of Idioms. © 2015 Farlex, Inc, all rights reserved.

tell things apart

to distinguish one thing or a group of things from another thing or group of things. This one is gold, and the others are brass. Can you tell them apart? Without their labels, I can't tell them apart.
See also: apart, tell, thing
McGraw-Hill Dictionary of American Idioms and Phrasal Verbs. © 2002 by The McGraw-Hill Companies, Inc.
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References in periodicals archive ?
By David Brown WASHINGTON--Learning to tell things apart and sort them into different piles is a key cognitive milestone of early childhood.
Firearms manufacturers must have some way to tell things apart and the most common way is to use model numbers.