胸部|きょうぶkyoubu[1]atamadaka (head-high)

1. nounchest; breast
   胸部きょうぶのレントゲンをとってください。↗

   I'd like you to have a chest X-ray.

• Synonym胸むねNeutralEveryday word for the chest, also used for the heart or feelings; 「胸部」 is the medical, written term for the body part.
• SynonymブレストNeutralLoanword for the chest or breast, also breaststroke; rarely used alone — say 「胸」 or 「胸部」 instead.
• Synonym胸元むなもとNeutralThe area around the chest, often the neckline of clothing, as in 「胸元が開いた服」.
• Synonym胸板むないたNeutralRefers to the chest itself, often when describing how thick a man's chest is; colloquial.
• Synonym胸先むなさきNeutralThe front of the chest or bosom area; fairly rare and not a medical anatomical term.
• Synonym胸間きょうかんWrittenWritten and rare; can mean the chest area or the heart and mind, while 「胸部」 refers only to the body part.
• SynonymチェストNeutralLoanword for the chest, common in fitness contexts; also means a chest of drawers.
• Antonym背部はいぶNeutralThe back; the direct opposite of 「胸部」, and likewise a medical-sounding term.

For medical or written use, say 「胸部」, as in 「胸部レントゲン」. In daily conversation 「胸」 is the default; use 「胸元」 for the neckline area and 「胸板」 for the chest itself. The loanwords ブレスト and チェスト have limited uses; 「背部」 is the back.

Usage comparisons are AI-assisted and cross-checked by multiple models; for study reference only

1. 胸むねの部分ぶぶん。
2. 呼吸器こきゅうき。