figure comprised of capital gammas; swastika
• (n.) A cross formed of four capital gammas, formerly used as a mysterious ornament on ecclesiastical vestments, etc. See Fylfot.
Gam·ma'di·on noun A cross formed of four capital gammas, formerly used as a mysterious ornament on ecclesiastical vestments, etc. See Fylfot . 
gammadion A pattern consisting of four capital Greek gammas (tetra-gammadion), especially when joined at the center to form a swastika or a very old symbol used by many ancient cultures.