also: ようえん
heat haze; heat shimmer
The shimmering or wavy appearance of air above hot surfaces, such as asphalt in summer.
A heat haze was shimmering above the summer road.
The distant scenery looks wavy because of the heat shimmer.
Standard kanji spelling; the reading かげろう is a jukujikun.
Rare on'yomi reading; learners will almost always encounter かげろう.
Kana spelling is common and avoids the unusual reading of the kanji.
An old native word, attested as かぎろひ and later かげろう, for the wavering shimmer seen in heated air. 陽炎 is a meaning-based spelling.