kigo

A seasonal reference word used in haiku to anchor the poem to a specific moment in the year — not a calendar marker but a compressed sensory package. "Cherry blossoms" carries the full weight of spring's beauty and brevity. "Cicadas" is summer. "Harvest moon" is autumn. The Japanese compiled formal encyclopedias of these — the saijiki — containing thousands. A kigo is the smallest possible landscape description: an entire season in a word.