arbor ar-bor / är-bər noun 1. a place shaded by trees or shrubs The sight of a pleasant arbor puts it in our mind to sit there. “The Art of Public Speaking” by Dale Carnagey (AKA Dale Carnegie), 1888 – 1955, and J. Berg Esenwein, 1867 – 1946 2. a framework that is covered with vines or other climbing plants that provides shade I never saw such a garden–large and shady, full of box-bordered paths, and lined with long grape-covered arbors with seats under them. From “The Yellow Wallpaper” by Charlotte Perkins Gilman, 1860 – 1935 3. (plural abores) Latin, a tree Arbores loqui latine. The trees speak Latin. From “The Dream Thieves” by Maggie Stiefvater, 1981 – 4. an axle or spindle on which a wheel or pinion revolves When the stem is turned, the pinion turns the crown wheel, which turns the ratchet wheel connected to the mainspring arbor, winding the spring that makes the watch go. David Boettcher, “About Watch Movements” https://www.vintagewatchstraps.com/watchmovement.php, 3-5-2020 5. an axis or shaft supporting a cutting tool or the rotating part of a lathe The standard milling machine arbor has a tapered, cylindrical shaft with a standard milling taper on the driving end and a threaded portion on the opposite end to receive the arbor nut. https://smithy.com/machining-handbook/chapter-4/page0 Etymology from the Latin noun arbor, arboris (tree, beam) Etymology provided by Allen Ward.