πέταλον

Greek pétalon meant 'leaf,' 'thin plate,' or a sheet of beaten metal — from petannynai, 'to spread out.' The word was used by Greek botanists including Theophrastus, Aristotle's student, who wrote the first systematic works on plant biology around 300 BCE. Theophrastus used pétalon broadly; the specific restriction to 'the colored parts of a flower' happened later, as botanical terminology narrowed. The word entered English in the early eighteenth century through New Latin petalum, formalized in Linnaeus's taxonomic system.

Petals are not decorative. They are advertisements. Their color, shape, and scent evolved to attract pollinators — bees, butterflies, moths, birds, and bats. Petal color is determined by pigments: anthocyanins produce reds, blues, and purples; carotenoids produce yellows and oranges; betalains produce the intense reds of beets and bougainvillea. A flower without petals (like grasses and many trees) relies on wind pollination and does not need to advertise. Petals exist because animals exist.

The Japanese practice of hana-fubuki — the 'flower blizzard' of cherry blossom petals falling in wind — has no exact equivalent in English. The Victorians developed an elaborate 'language of flowers' (floriography) in which specific petals carried coded messages: a red rose petal meant love, a yellow one meant jealousy, a white one meant purity. The system was complex enough to fill books and vague enough to cause misunderstandings. The medium was unreliable. The petals were beautiful.

The word petal now appears in contexts the Greeks would not recognize. Petal is a common name in Greek (Πέταλο). Metal petals are used in engineering for retractable dome roofs. The verb 'to petal' does not exist in English, but 'to depetal' (removing petals) does, in botanical literature. The thin, spread-out thing that the Greeks named has been spread very thin indeed.