fighter and magic-user (1st Ed.) -- you can't find these in dictionary. They are D&D specific.
saving throws -- original concept
armor class (AC)
hit point, hit dice
dice d4, d8, d10, d12, d20, d30, d100, d% (#d#+#, eg 2d4+2)
gold, silver, copper, brass, bronze dragon; red, blue, green, black...