Denshi Jisho — Online Japanese dictionary

一層 いっそう 1:
2: (Usually written using kana alone) much more; still more; all the more; more than ever; () single layer (or storey, etc.);
3: (Adverb) (Archaism) rather; sooner; preferably
Common word, Adverb, No-adjective 
一層目 いっそうめ first layer
Noun 

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