An ornamental pin attached to clothing in a person's upper chest area.(noun)
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Use "breastpin" in a sentence
"He wore no ornaments, except ear-rings, a plain breastpin, and one or two rings on the fingers."
"She wears an oldfashioned apron all the time and in cool weather there is always a little black cape around her frail shoulders and held together with a plain old gold "breastpin"."
""I won't insult your intelligence by telling you how I read that, especially as, rather against the strict rules of your order, you use an arc-and-compass breastpin.""