Christmas cake
White layer cake iced with whipped cream and strawberries. Because Christmas cake is eaten on Christmas, the expression "your Christmas cake is going stale" once referred to an unmarried woman over the age of 25. These days, though, with a birth rate of 1.34 and over half of the 26-30 population never married, the use-by date on this metaphor has mostly expired.

Acronym guide
An (ahn)
Geta
Haori hakama
Happi coat
Kansai-ben
Kobe
Koseki
Home literature
Meiji Period
Mikoshi
Pat Morita
Mutual
Nakamozu
Natsume Soseki
Obi
Okuribi
O-furo
Osaka
Sada Masashi
Seijinshiki
Sendai
Shiromuku uchikake
Tanzaku
Tatami
Terms of address
Tsuno-kakushi
Yukata

A useful compendium of Mormon ecclesiastical and theological terminology can be found here.