bonnet rouge

Century Dictionary and Cyclopedia

1. n. The cap of liberty of the French revolutionists of 1793. See liberty-cap.
2. n. Hence A wearer of such a cap; a sans-culotte.
3. n. A red republican; an anarchist or communist.

GNU Webster's 1913

1. The red cap adopted by the extremists in the French Revolution, which became a sign of patriotism at that epoch; hence, a revolutionist; a Red Republican.