水素: hydrogen

(phonology, orthography, grammar) the third row of the 五十音図 (literally “table of the fifty sounds”), consisting of the five kana さ/サ (sa), し/シ (shi), す/ス (su), せ/セ (se) and そ/ソ (so)

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to be overturned / (of one's voice) to crack for a moment