Denshi Jisho — Online Japanese dictionary

凸 でこ brow; forehead
Noun, Usually written using kana alone, Sensitive 
凸 とつ convex
Na-adjective, No-adjective 
お凸 おでこ 1: (Usually written using kana alone) (Sensitive) brow; forehead;
2: (Usually written using kana alone) prominent forehead; beetle brow;
3: (Usually written using kana alone) (Colloquialism) not catching anything (in fishing)
Common word, Noun 
御凸 おでこ 1: (Usually written using kana alone) (Sensitive) brow; forehead;
2: (Usually written using kana alone) prominent forehead; beetle brow;
3: (Usually written using kana alone) (Colloquialism) not catching anything (in fishing)
Noun 
凹凸 おうとつ unevenness; roughness; ruggedness
Common word, Noun, Na-adjective, No-adjective 
両凸 りょうとつ biconvex
Noun, No-adjective 

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