which is which

1. What particular one is what particular one, or what is the difference between different ones. For example, These twins look so much alike I can't tell which is which, or Both our raincoats are tan; do you know which is which? This idiom was first recorded about 1412.

Example Sentences

Each Cabinet wall is given over to a particular season, and while there are no labels to tell you which is which, the characteristics of these transportive, nature-focused murals instantly position us in a particular environment.

Read more on The Wall Street Journal

“One’s a boy and one’s a girl,” Madame Ionesco said, “but don’t ask me which is which.”

Read more on Literature

“There's a lot of misinformation, but I do think there is a lot of good information out there, and it's just that it comes to a point when it's very difficult to separate which is which,” he said.

Read more on Salon

"You've got to do your research and really study and master the craft of telling which is which, as it's such a big problem now," said Jacob, who runs Knight Vintage in Cardiff.

Read more on BBC

ABC’s decision to pay Trump and apologize nonetheless is an Orwellian warning that, when covering an ascendent fascist, up will be down and down will be up, and only Trump can decide which is which.

Read more on Salon