A piece of defensive armor, covering the body from the neck to the girdle
- A piece of armor for protecting the breast and back.
- The breastplate alone.
- A defense or protection: "A carefully primped irony, that cuirass of art in the early Eighties, is necessary—a distance so affected as to constitute a hopeless impediment to feeling” ( Robert Hughes).
- Zoology A protective covering of bony plates or scales.
- To protect with a cuirass.