The term 'breastbones' is used to refer to two different bones in the human body. The first is the sternum, which is an elongated flat bone located in the center of the chest and is also known as the breastbone. The second is the sterna, which are a pair of curved bones located at the base of the neck and are also known as collarbones. Both of these bones play an important role in providing support and protection for the chest and neck area.