Denshi Jisho — Online Japanese dictionary

瓦斯 がす gas
Ateji (phonetic) reading, Noun, No-adjective, Usually written using kana alone, dut:, eng: 
瓦斯灯 ガスとう gas light; gas lamp
Ateji (phonetic) reading, Noun 
瓦斯燈 ガスとう gas light; gas lamp
Ateji (phonetic) reading, Out-dated kanji, Noun 

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