御金[okane] money
金糸雀[kinshijaku] canary (esp. the island canary, Serinus canaria)
違約金[iyakukin] penalty for contract breach
一刻千金[ikkokusenkin] every moment is precious
一字千金[ichijisenkin] word of great value

一時金[ichijikin] lump sum
一時賜金[ichijishikin] lump-sum grant
引き金を引く[hikiganewohiku] to pull the trigger
引当金[hikiatekin] reserves
隠れ借金[kakureshakkin] hidden debts

黄鉄鉱[outekkou] iron pyrites
可鍛鉄[katantetsu] malleable iron
狭軌鉄道[kyoukitetsudou] narrow-gauge railway
近鉄[kintetsu] Kinki Nippon Tetsudou (railway co.)
剣付き鉄砲[kentsukideppou] fixed bayonet

甲鉄[koutetsu] armor
甲鉄艦[koutetsukan] armored ship
甲鉄板[koutetsuban] armor plate
鋼鉄[koutetsu] steel
国鉄[kokutetsu] national railway (esp. Japan National Railways)

お歯黒[ohaguro] tooth blackening
暗黒期[ankokuki] eclipse period
暗黒時代[ankokujidai] Dark Ages
暗黒大陸[ankokutairiku] Dark Continent (i.e. Africa)
黒い[kuroi] black

黒い霧[kuroikiri] thick fog
黒くする[kurokusuru] to blacken
黒ずむ[kurozumu] to blacken
黒っぽい[kuroppoi] dark