Meaning of TAIL in English
( n. )
The side of a coin opposite to that which bears the head, effigy, or date; the reverse; -- rarely used except in the expression "heads or tails," employed when a coin is thrown up for the purpose of deciding some point by its fall.
Webster's Revised Unabridged English Dictionary. Пересмотренный полный словарь английского языка Webster. 2012