Origins
The English word 'broom' presents one of the language's most transparent cases of metonymy — a thing named after the material it is made from. The word originally referred exclusively to a thorny yellow-flowering shrub of the genus Cytisus, particularly Cytisus scoparius (common broom or Scotch broom), whose long, straight, flexible green branches were ideal for bundling into sweeping implements. By the late Old English period, the tool made from broom branches had acquired the plant's name, and by Modern English the sweeping-tool meaning has so thoroughly eclipsed the botanical meaning that most English speakers are unaware the plant exists.
Old English 'brōm' comes from Proto-Germanic *brāmō, meaning a thorny bush or shrub. This root also produced Old English 'brēmel' (bramble, the thorny berry bush), German 'Brombeere' (literally 'broom-berry,' i.e., blackberry), and Dutch 'braam' (bramble). The relationship between 'broom' and 'bramble' has been obscured by centuries of sound change, but both words describe thorny shrubs and share the same Germanic ancestor.
The broom plant itself has had an outsized impact on European history and culture. Most famously, it gave its name to the Plantagenet dynasty, which ruled England from 1154 (Henry II) to 1485 (Richard III). According to medieval tradition, Geoffrey V, Count of Anjou and father of Henry II, wore a sprig of the broom plant — called 'planta genista' in Latin — in his hat as a personal badge. The nickname 'Plantagenet' was not widely used during the dynasty's actual reign but was popularized by later historians. The Latin species name 'scoparius' (of the broom) independently confirms the sweeping connection: Latin 'scopae' means a broom or besom, so the plant was literally 'the broom-plant' in Latin as well as in English.
Word Formation
The transfer from plant-name to tool-name was gradual and overlapping. The earliest clear reference to 'broom' meaning the sweeping implement dates from around 1000 CE, but the plant meaning persisted in parallel for centuries. The compound 'broomstick' — the stick or handle to which the broom-plant bundle was attached — dates from the fifteenth century. 'Broomstick' later became famous through its association with witchcraft: the image of a witch riding a broomstick is documented from at least the fifteenth century and may reflect older folk beliefs about household implements as vehicles for spirit flight.
The verb 'to sweep' itself comes from Old English 'swāpan' (to sweep, rush, brandish), and the tool was also called a 'besom' (Old English 'besma,' a bundle of twigs) — a word that survives in dialectal British English and Scottish English to this day. The displacement of 'besom' by 'broom' in standard English demonstrates how powerfully material metonymy can reshape vocabulary: the specific plant used to make besoms became so associated with the object that its name replaced the generic term.
'Broomcorn' (Sorghum bicolor var. technicum) — a variety of sorghum grown specifically for its long, stiff seed heads used in making brooms — was named by analogy in the eighteenth century. When American broom-makers shifted from the European broom plant to this more readily available New World grass, the name 'broom' transferred to the new material, extending the metonymic chain: the plant named the tool, and the tool named a completely different plant grown to make it.
Later History
In place names, 'broom' appears frequently across England: Bromley (broom meadow), Bromwich (broom farm), Broomfield (broom field), and dozens of others testify to the plant's abundance in the medieval English landscape. These place names preserve the botanical meaning that everyday language has largely forgotten.
The broom plant's ecological story is equally dramatic. Introduced to North America, Australia, and New Zealand as an ornamental and soil-stabilizer, Cytisus scoparius has become one of the world's most aggressive invasive species, colonizing disturbed land and displacing native vegetation across temperate regions. The plant that gave its name to an English dynasty and a ubiquitous household tool is now an ecological menace on three continents — a trajectory as improbable as any word's etymological journey.