What is the meaning of the word "bosom"?

Definitions:

Describes a close, affectionate relationship. NOUN
- They were bosom friends, having shared every major life event together.
Describes a place of safety, comfort, or nurturing. NOUN
- She returned to the bosom of her family after many years abroad.
Refers to the chest or breast area of a person, particularly a woman's breasts. NOUN
- She held the child close to her bosom, comforting him.
Used figuratively to refer to the heart, emotions, or the innermost feelings and thoughts, often representing a place of deep affection or intimacy. NOUN
- He shared his deepest secrets with his bosom friend.