Citron

As the citron resembles the hand of buddha, it is called foshao (佛手）in chinese.  Foshou sounds similar to fu (福 meaning happiness） and shou (寿 meaning longevity.  Hence,  it symbolises happiness and longevity.  

It is also commonly depicted together with peach and pomegranate to convey the auspicious meaning of sanduo (3 abundances).