mayfly
Refers to the insect order Ephemeroptera. In everyday use, the kana form かげろう is standard.
On a summer evening, many mayflies were flying above the river.
ephemerality; transience of life
Metaphorical use, often in literary or poetic contexts, likening life to the short-lived mayfly. Common in phrases like かげろうの命.
He spoke feelingly that human life is like that of a mayfly.
Only when written 蜻蛉
Archaic word for dragonfly. In modern Japanese, トンボ is used instead. The kanji 蜻蛉 is now read as とんぼ or せいれい.
See also: トンボ
In old waka poetry, 蜻蛉 is sometimes read as かげろう.
green lacewing
neuropteran; lacewing or antlion (order Neuroptera)
antlion; lacewing larva
Archaic kanji form for dragonfly, now normally written トンボ. The reading is a gikun.
Katakana spelling is sometimes used, especially in biological or field-guide contexts.
Rare kanji form for mayfly and the associated ephemerality metaphor. The reading is a gikun (meaning-based reading).
The word is native Japanese. The kanji 蜉蝣 and 蜻蛉 are Chinese borrowings applied as gikun (meaning-based readings) to the existing Japanese word かげろう. The exact origin of かげろう is uncertain.