linguistic:paraphrasing
Kigo

A haiku traditionally contains a kigo, a word or phrase that symbolizes or implies the season of the poem and which is drawn from a saijiki, an extensive but prescriptive list of such words. Season words are evocative of images that are associated with the same time of year, making it a kind of logopoeia. Kigo are not always included in non-Japanese haiku or by modern writers of Japanese free-form haiku.