swastika (n.)
Greek cross with arms bent at right angles, 1871 (in English specifically as emblem of the Nazi party from 1932), from Sanskrit svastika-s, literally "being fortunate," from svasti-s "well-being, luck," from su- "well" (from PIE *(e)su- "good") + as-, root of asti "(he) is," which is from the same PIE root as Latin esse "to be" (see essence).

Also known as gammadion (Byzantine), cross cramponnee (heraldry), Thor's hammer, and, perhaps, fylfot. Originally an ancient cosmic or religious symbol thought to bring good luck. Use in reference to the Nazi emblem first recorded in English in 1932. The German word was Hakenkreuz, literally "hook-cross."