tell apart = see the difference between similar things
- The twins are so much alike! Only their parents can tell them apart.
- These two pictures are the same. There is no difference between them. You can't tell them apart.
- You can hardly tell their handwriting apart. They almost write in the same way.
- It is difficult to tell a forged signature apart from a real one.
- I can never tell their voices apart. They sound the same.