Z is for Zero

Z is for Zero, from Arabic 'sifr', originally meaning empty, but coming to be used for zero, and its use is quite significant to the development of mathematics. Lots of interesting stuff out there about the history of the concept of nothing, on Wiki and the book 'Zero: the biography of a dangerous idea'. 

Linking back to the A to Z Challenge.

Found this image on wikimediacommons, it shows the first known graphic representation of zero. On a broken doorjamb, from Trapeang Prei, Sambor, Kratie. Now on display at the National Museum of Cambodia