Denshi Jisho — Online Japanese dictionary

何故 なぜ why; how
Common word, Adverb, Usually written using kana alone 
何故か なぜか somehow; for some reason; without knowing why
Common word, Adverb 
何故 なにゆえ why; how
Common word, Adverb, Usually written using kana alone 
何故なら なぜなら because
Common word, Conjunction, Usually written using kana alone 
何故ならば なぜならば because; for; the reason why is ...
Common word, Conjunction, Usually written using kana alone 
何故かと言うと なぜかというと because; the reason why is
Expression 

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