What mean of a bosom friend in idioms?

The idiom "bosom friend" refers to a very close and trusted friend, someone you confide in and share your deepest secrets with.

Here's how it breaks down:

* Bosom: Originally meant the chest area, but here it implies a place of intimacy and trust.

* Friend: Someone you have a close relationship with.

Putting them together, "bosom friend" creates a powerful image of a friendship that is deep, intimate, and unwavering.

Here are some examples of how it's used:

* "I confided in my bosom friend about my secret crush."

* "She's been my bosom friend since childhood."

* "He considers his business partner his bosom friend."