ライン川[raingawa] (river) Rhine
安倍川餅[abekawamochi] rice cakes (mochi) with Kinako
川床[kawadoko] riverbed
河川[kasen] rivers
江川る[egawaru] to (try to) act like a big-shot

香川県[kagawaken] Kagawa prefecture (Shikoku)
三途の川[sanzunokawa] Sanzu River (Buddhist equivalent of the River Styx)
山川[sansen] mountains and rivers
四川[shisen] Sichuan (China)
小川[ogawa] streamlet

サンプリング周波数[sanpuringushuuhasuu] sampling frequency
波蘭[poorando] Poland
マイクロ波[maikuroha] microwave
ミリ波[miriha] milli-wave
圧力波[atsuryokuha] pressure wave

伊呂波[iroha] traditional ordering of the Japanese syllabary
浦波[uranami] (seaside) breakers
横波[yokonami] side (transverse) wave
音波[onpa] sound wave
寒波[kanpa] cold wave