Refers to the area around the chest, especially the upper front of the body. Often used in contexts of clothing, accessories, or physical description.
She covered her chest with a scarf.
She wore a small brooch at her chest.
That dress has a deep neckline.
pit of the stomach; solar plexus; epigastrium
Refers to the upper central part of the abdomen, just below the sternum. Often used in medical or anatomical contexts, or when describing a feeling in that area.
I felt a tightness in the pit of my stomach from anxiety.
It hurts a little when I press on my solar plexus.
He punched me in the solar plexus and I couldn't breathe for a moment.
She wore a small necklace at her neckline.
Hearing the news, I felt a tightness in my stomach.
みぞおち is the everyday word for the pit of the stomach, whereas 胸元 in this sense sounds more formal or anatomical.
乳房 refers specifically to the breast itself, while 胸元 more broadly describes the exposed chest area near the collar, as in clothing.
Standard kanji spelling; common in news and everyday writing.
Mixed kanji-kana spelling; less common but still encountered.
Rare kanji form; it is rarely used.
Compound of 胸 (muna, 'chest') + 元 (moto, 'base, origin'). The reading muna is an older combining form of mune.