What does the phrase "in the dark" mean and what are some examples?

“In the dark” is an idiom that means you are unaware of something, usually because someone deliberately kept it from you.

An idiom is a commonly used figure of speech.  It is a simile or metaphor, but it is used so often that most people have heard it and know what it means.  This phrase is an idiom.  Other idioms include “it’s raining cats and dogs” and “beat around the bush.”  A similar idiom is...

“In the dark” is an idiom that means you are unaware of something, usually because someone deliberately kept it from you.

An idiom is a commonly used figure of speech.  It is a simile or metaphor, but it is used so often that most people have heard it and know what it means.  This phrase is an idiom.  Other idioms include “it’s raining cats and dogs” and “beat around the bush.”  A similar idiom is "out of the loop."  It also means someone did not tell you something.

The phrase “in the dark” is usually used when a person does not know something that he or she should know.  Sometimes it means that people deliberately did not tell the person what he wanted to know or should have known.  It’s a metaphor because if you are literally in the dark, you can’t see.

Here is an example about the phrase.

When Jenny broke up with her boyfriend she kept her friends in the dark about it because she was embarrassed.

In this case, Jenny deliberately did not tell her friends that she broke up with her boyfriend, so her friends were in the dark.  Jenny kept a secret from them.  You can use this phrase about any kind of lack of knowledge though.

I was in the dark about the band schedule.

This person did not know what the band schedule was, so he is in the dark.  Maybe he forgot to check, or maybe he just forgot.  Either way, he did not know what was going on.