胸むね三さん寸ずんむねさんずんMeanings1nounheart; mind; feelingsIdiomatic expression referring to one's inner thoughts, emotions, or true intentions, literally 'three inches inside the chest'. Often used in set phrases like 胸三寸に納める (keep to oneself) or 胸三寸で決まる (be decided by one's heart).本ほん当
