1The generation or production of heat (e.g., heat produced by chemical reactions or mechanical friction).
化学反応による発熱で温度が急上昇した。
The temperature rose rapidly due to heat generated by the chemical reaction.
エンジンの異常な発熱は故障の兆候だ。
Abnormal heat generation in the engine is a sign of malfunction.
2An episode of fever; an elevated body temperature due to illness or infection (fever).
昨夜から発熱があり、今日病院で診てもらった。
I had a fever since last night and saw a doctor today.
子どもが急に発熱したので保育園から連絡が来た。
The daycare called because the child suddenly developed a fever.
新型ウイルス感染では発熱がよく見られる症状だ。
Fever is a common symptom in infections with the new virus.
熱は下がったが、発熱の原因を調べるため再診した。
The fever went down, but I went back for a follow-up to find the cause of the fever.