# Why are imaginary numbers called imaginary numbers

Why do we call imaginary numbers "imaginary numbers"? As far as I can tell, there's nothing really imaginary about them. They exist. They're used all the time. What makes them so "imaginary"?

• Because "irrational numbers" was already in use. May 7, 2012 at 6:43
• The term is historical. When they were originally invented, people thought there might be something wrong with them. Now we know there's nothing wrong with them, but the term has stuck.
– Ted
May 7, 2012 at 6:45
• You might want to read this. As Ted says, it's really unfortunate terminology, just as with our use of the adjective complex... May 7, 2012 at 6:46
• @ J.M. That was an informative article too. May 7, 2012 at 6:56

• +1 for the reference and an imaginary +1 for fancied numbers.