English meets cecropia in two habitats that have almost nothing in common. One is a giant silk moth of eastern North America, brown-winged, red-banded, and large enough to fill a hand. The other is a genus of fast-growing trees that colonize gaps in tropical American forest, hollow-stemmed, with palmate leaves bunched at the tips of the branches. Both uses are common nouns taken from the same learned Latin label. Neither grew in Old English, and neither is a folk name that scientists later dressed in classical clothes.
The moth is Hyalophora cecropia, North America’s largest native saturniid. Field English also says cecropia moth; entomologists often drop moth and treat cecropia as the insect itself. Adults live only about two weeks, without working mouthparts, and the caterpillars feed on maple, cherry, birch, and a long list of other trees. The plants are genus Cecropia, dioecious pioneers of the Neotropics. English sometimes calls them trumpet trees or pumpwoods; in the countries where they actually stand, older vernaculars such as guarumo, yarumo, and yagrumo remain the everyday words. The English noun covers both lineages without choosing between them.
A Linnaean label, twice
The origin of the word cecropia is a New Latin coinage from a Greek royal name, not a woodland term that later went to school. In 1758 the Swedish botanist Pehr Löfling published the plant genus Cecropia in Iter Hispanicum, a travel flora issued by Linnaeus after Löfling’s death. The genus honors Cecrops, the legendary first king of Athens. Linnaeus described the type species Cecropia peltata the following year, and botanical codes have conserved the generic name ever since.
The moth received the same epithet in the same year, by a separate act of naming. In the tenth edition of Systema Naturae, Linnaeus listed the insect as Phalaena cecropia. Later workers moved it through Samia and Platysamia; it now stands as Hyalophora cecropia. The specific epithet is the Latin feminine adjective used as a species name, ordinary practice in eighteenth-century scientific Latin. Botanists and entomologists did not copy one another’s English. They each reached for the same Attic adjective because Linnaean taxonomy liked Greek legendary names.
English had little need of the word until natural-history prose in the nineteenth century. A Brazilian travel narrative of 1824 already uses cecropias for the trees. Dictionaries date the American moth name later: some place cecropia moth around 1865–70, Merriam-Webster at 1885. The discrepancy is which printed source a lexicographer counted first, not a change of sense. Shorter notices simply mark the English noun as nineteenth-century Modern Latin from Cecrops.
Athenian on paper
The Latin source is Cecropia, feminine of Cecropius, meaning Athenian or Attic. That adjective is a straight borrowing of Greek Kekropios, of Cecrops, from the personal name Kekrops. In classical Greek the same family did civic work: Kekropia could stand for Athens or the Acropolis; the Kekropidai were Athenians as descendants of the first king. English already had the poetic adjective Cecropian in that learned stream. The biological noun is the feminine form frozen as a name and then treated as an ordinary countable, with the English plural cecropias.
Morphology is thin because the borrowing is complete. No native prefix or suffix was added. New Latin took the feminine adjective and used it as a genus and as an epithet; English lifted the Latin shape as-is. A later scientific derivative, cecropin, names antimicrobial peptides first isolated from the moth. That formation belongs to twentieth-century biochemistry. It is not an older sense of the headword, and it does not help explain how the noun entered English.
The king whose name may not be Greek
Myth made Cecrops autochthonous, born from the soil of Attica, a culture hero credited with writing, marriage, and ceremonial burial. Artists and scholiasts gave him a man’s torso and a serpent’s lower body and called him diphyes, of two natures. Popular nature writing sometimes leans on that image and glosses the moth’s name as face with a tail, pointing at wing tips that can resemble a snake’s head. The picture is vivid. It is not how historical linguists treat Kekrops.
The personal name is of uncertain etymology. Ancient writers already felt it was not native Greek: Hecataeus called it a barbarian name, and Strabo likewise treats Cecrops as non-Greek. Modern etymological dictionaries of Greek class it as Pre-Greek. One twentieth-century proposal would rearrange it from a form Kerkops, provided with a tail, built on Greek kerkos, tail. That would tie the snake-bodied king, the folk gloss, and the moth’s eyespots to a transparent Greek root. Specialists generally reject the metathesis as improbable. A Pre-Greek formation with reduplication, of a type seen in other names such as Merops, is the cautious account. Where the evidence stops, so should the story: English inherited a classical epithet whose deepest layer remains unexplained.
Cognates are the expected classical set rather than a Germanic family. Latin Cecropius and Greek Kekropios, Kekropia, and Kekropidai sit on the same stem. English Cecropian is a sibling learned borrowing, not a descendant of the biological noun. There is no Old English ancestor, and no chain of sense from forest to insect in ordinary speech.
Two namings, not a drift
Cecropia did not slide from tree to moth the way a word for a bird later names a machine. Two scientific acts in 1758 chose the same Attic adjective; nineteenth-century English then absorbed both labels as common nouns. A speaker who knows only the moth, or only the rainforest tree, is using one etymology by different routes.
Later taxonomy moved the containers, not the name. The moth’s genus has shifted; older books still print Platysamia cecropia or Samia cecropia, but the epithet stayed. The tree genus, once grouped with mulberries or in its own family Cecropiaceae, now sits in the nettles, Urticaceae. Again the Latin name held while the classification changed.
A last concrete remnant is geographic. Kekropia was an old name for the Athenian citadel. When a tropical pioneer tree or a New England silk moth is called cecropia, the word is still, at one remove, the Athenian one: a learned feminine adjective that New Latin turned into a species tag, and that English then treated as an everyday noun.