Ba zan iya samun kalmar "Adar Sheni" a cikin ƙamus na Turanci ba. Duk da haka, Adar Sheni kalma ce da aka yi amfani da ita a kalandar Yahudawa don yin nuni ga watan Adar na biyu, wanda aka ƙara a cikin shekarun tsalle. A cikin wadannan shekaru, akwai Adarar guda biyu, tare da Adar Sheni shine ƙarin watan. Ana yin haka ne don daidaita kalandar wata da na rana da aka yi amfani da su a al'adar Yahudawa.