decline in the number or proportion of children in the population due to a declining birth rate

an advance; progress

make progress

Short for 日本国 (Nihon-koku): Japan (a country and archipelago in East Asia) / a surname

Japan

(archaic) Japan

chord progression

(physics) travelling wave (wave that is not bounded by a given space, but can propagate freely)

Japanese food, Japanese cuisine

Japanese foods, Japanese cuisine