blōstm

Old English blōstm (also blōstma) comes from Proto-Germanic *blōsmô, from a root meaning 'to blow' or 'to burst forth.' The connection between blowing and blooming is physical: a bud opens the way a breath opens the mouth. The same root produced German Blust and Dutch bloesem. The word bloom, which seems like the obvious relative, actually entered English later from Old Norse blóm. The two words — blossom and bloom — are cousins from different branches of Germanic, reunited in English by the Viking invasions of the ninth and tenth centuries.

In English, blossom and bloom have subtly different uses. Blossom tends to refer to the flowers of fruit trees — cherry blossom, apple blossom, orange blossom — and carries connotations of something just beginning. Bloom is broader and can refer to any flower in full display, including garden flowers, algae (algal bloom), and even the flush on a person's cheeks. A child blossoms (develops). A flower blooms (opens). The Viking word and the English word divided the territory rather than fighting over it.

Japanese hanami (flower viewing) is the cultural practice of gathering beneath cherry blossoms in spring. The custom dates to at least the Nara period (710–794 CE), when aristocrats held blossom-viewing parties. The Japanese Meteorological Agency issues an annual cherry blossom forecast (sakura zensen), tracking the 'blossom front' as it moves northward from Okinawa in January to Hokkaido in May. The entire nation organizes around a flower opening. No other country treats a botanical event as national news.

Orange blossom water is a staple of Middle Eastern and North African cooking, distilled from the flowers of the bitter orange tree. The word blossom, when attached to orange, carries flavors of Lebanese pastry, Moroccan tea, and Spanish agua de azahar. The Old English word for a bud opening now names a perfume, a dessert ingredient, and a season.