#3: Sigil

Each of the noble families in Westeros has its own sigil – a "house seal" used as a stamp on correspondence and on armor. The sigil of the Starks, a prominent family in the series, is a direwolf. (Though the word direwolf sounds medieval, it's not. Dire wolf is the name of an extinct – and large–wolf species from the Pleistocene Epoch, and the word itself only dates back to the 1920s.)

A sigil isn't something unique to Game of Thrones. The use of sigils dates back to ancient Mesopotamia. Royal sigils were common from the 11th century onward, and by the 12th century, nobles and bishops were also commonly using seals.