tell the difference between

tell the difference between (someone or something)

To be able to discern or distinguish some person or thing as being distinct and unique compared to someone or something else. It's very difficult to tell the real paintings from the counterfeits, but there are a few things we can look for to be sure. Even I have trouble telling the difference between the two brothers, so I can understand your confusion. The court ruled that the man was psychologically unable to tell the difference between right and wrong when he committed the crime.
See also: between, difference, tell
Farlex Dictionary of Idioms.

tell the difference between (someone and someone else) (or something and something else)

to recognize the things that distinguish people or things. I can't tell the difference between Billy and Bobby. Sam can't tell the difference between Granny Smith and Royal Gala apples.
See also: between, difference, tell
McGraw-Hill Dictionary of American Idioms and Phrasal Verbs.
See also:
  • tell the difference between (someone or something)
  • tell (someone or something) from (someone or something else)
  • tell from
  • tell from else
  • tell from else Go to tell from
  • know (someone or something) from (someone or something else)
  • know from
  • know from something
  • tell (someone or something) by (something)
  • tell by
References in classic literature
Couldn't ever tell the difference between a sheet and a tackle, simply couldn't.
South Sea Tales
The technology is capable of picking up on the subtler distinctions between the same brand aged in different barrels, with more than 99 per cent accuracy and able to tell the difference between those aged for 12, 15 and 18 years.
Techno 'tongue' spots fake booze
The technology is capable of picking up on the subtler distinctions between the same brand aged in different barrels, with more than 99% accuracy, and able to tell the difference between those aged for 12, 15 and 18 years.
Artificial 'tongue' could detect counterfeit dram; ? Metal tastebuds' potential for food safety, quality and security
Penn State food scientists recruited a total of 292 regular ice-cream consumers to take part in the blind taste tests to determine their overall acceptability of various fat levels in fresh ice cream and to see if they could tell the difference between samples.
Does ice cream with more fat really taste better?
The intelligent system can tell the difference between a real fire and common causes of false alarms, and is designed to be as minimally visible as possible.
Mold fire safety firm wins contract for Moneypenny office
I don't Know if people can tell the difference between DRINKING that and a bottle of Alpine spring water, unless I need to see the doc about my taste buds.
Buying water; MAILBAG
Your customers can tell the difference between an organization that lives the values that trust represents and one that doesn't.
How much do you care?
IT'S hard to tell the difference between Tana Ramsay and Victoria Beckham these days, as this picture shows - almost identical jeans, vest, shades, even hair.
IT'S hard to tell the [...]
Truth is we're imposters, old fogeys into our mid-30s who couldn't tell the difference between dubstep and stairlift.
TOO OLD FOR EXAMPLE?
can buy a cut-price suit along with your groceries - and can most of us even tell the difference between budget or blowout?
One is pounds 565three under pounds 60, [...]
Davies adds: "It has proven very popular and in taste tests 75% of people failed to tell the difference between Brains Black and Guinness, and even amongst those who did detect a difference a high proportion found Brains Black more appealing taste-wise."
Brains' brainwave - selling Welsh stout in Ireland
Pensioners' Forum Wales says member of the public can find it hard to tell the difference between charity collection bags and ones that private companies use to collect goods that they sell to make a profit.
Charity bags 'need clearer labelling'
Bemused shoppers struggled to tell the difference between the 18-year-olds, from London, who were dressed the same and mirrored one another's movements.
Can you spot the difference?
Travel agents who cater to clients striving to be environmentally friendly need to be able to tell the difference between a resort that really is green and those that are "green-washing." Bucuti Beach CEO Ewald Biemans offers suggestions for ways to tell the difference.
Travel Environment Watch - North America