Reverse

Reverse – the 'back' side of a coin and the opposite of the obverse or 'front'. The reverse is also commonly referred to as 'tails' since the obverse, or 'heads' side of the coin often features the King or Queen of its country of issue in the form of an official portrait of their 'crowned head'.  The reverse of a coin is generally of greater interest to collectors since it's the side that carries the design in annually changing series such as the UK Lunar Shēngxiào Collection or the China Panda.