popularity

presence of people

(formal) someone's age

Kyūjitai form of 代数学 (“algebra”)

once-in-a-lifetime (event)

the Phanerozoic eon

a male given name

the Seven Generations of Heavenly Gods, including 国常立 (Kuni no Tokotachi) of the first, 豊雲野 (Toyokumono) of the second, 埿土煮 (Uijini) and his sister 沙土煮 (Suijini) of the third, 角杙 (Tsunogui) and his sister 活杙 (Ikugui) of the fourth, 大戸之道 (Ōto no Ji) and his sister 大戸之部 (Ōto no Be) of the fifth, 面足 (Omodaru) and his sister 綾惶根 (Ayakashikone) of the sixth, and 伊弉諾 (Izanagi) and his sister 伊弉冉 (Izanami) of the seventh

layer upon layer; level by level; multi-layered

layer, level