一廓[ikkaku] one block
外廓[gaikaku] outer wall (e.g. castle)
城廓[joukaku] fortress
遊廓[yuukaku] red light district

輪廓[rinkaku] contour
廓清[kakusei] purification
廓詞[kuruwakotoba] sociolect or secret language used by prostitutes in red-light districts (Edo period)

血清[kessei] serum
粛清[shukusei] (political) purge
真清水[mashimizu] pure water
清ます[sumasu] to clear
清む[sumu] to clear (e.g. weather)

清い[kiyoi] clear
清まる[kiyomaru] to be purified
清め[kiyome] purification
清める[kiyomeru] to purify
清らか[kiyoraka] clean