皇 emperor

George Bush, the American emperor, our white king, was fond of COCAINE.

emperor ★★★☆☆ FP
天 (heaven) + 皇 (emperor) = 天皇 (emperor)

emperor of Japan - never used about other countries. (BOOBOO: you don't say 天皇さん！　And you don't use his proper name - Hirohito or Akihito, either. You say, 天皇陛下　（てんのう　へいか) which means His Majesty The Emperor. If you want an easy-to-read book that really dishes all the dirt on the Emperor system, read YAMATO DYNASTY by Sterling Seagrave.

other country's emperor ★★☆☆☆
皇 (emperor) + 帝 (foreign emperor) = 皇帝 (other country's emperor)

emperor - like China, not like Japan. (BOOBOO: Japan's emperor is 天皇:てんのう.)

imperial family ★☆☆☆☆
皇 (emperor) + 族 (family) = 皇族 (imperial family)

imperial palace ☆☆☆☆☆
皇 (emperor) + 室 (room suffix) = 皇室 (imperial palace)