noun
breastplate; chest protector
Protective gear worn over the chest, such as in sports, martial arts, or historical armor.
剣道の防具には胸当てが含まれている。
Kendo protective gear includes a chest protector.
野球のキャッチャーは胸当てを着用する。
Baseball catchers wear a chest protector.
noun
A bib worn to protect clothing, especially for babies or during meals.
赤ちゃんに胸当てをつけて離乳食をあげた。
I put a bib on the baby and fed them baby food.
Search-only kanji form; not a standard spelling.
Irregular okurigana variant; less common but still encountered.
Compound of 胸 (mune, 'chest') and 当て (ate, 'pad, guard'). The reading むなあて is a common euphonic change (mune → muna) in compounds.