Merriam-Webster's Word of the Day for April 28, 2023 is: arboreal \ahr-BOR-ee-ul\ adjective

Arboreal is a literary term that means “of or relating to trees.” It can also mean “living in or often found in trees,” as in “arboreal monkeys.”

// Despite taking weekly hikes on the same trail, she never ceases to be amazed by the forest’s arboreal beauty.

[See the entry >](https://www.merriam-webster.com/dictionary/arboreal)

Examples:

“[The satanic leaf-tailed gecko's] mottled brown skin, replete with mossy splotches and vein-like ridges, makes it the perfect imitation of a decaying leaf. Any predator clever enough to see through its arboreal disguise and mount an attack will be in for a fright. The leafy gecko opens its mouth, sticking out a blood-red tongue and unleashing a chilling scream that will frighten off the boldest of predators.” — Holly Barker, Discover Magazine, 7 Oct. 2022

Did you know?

Arboreal took root in English in the 17th century, at a time when language influencers were eager to see English take on words from Latin and Greek. Apparently unsatisfied with the now-obsolete word [treen](https://www.merriam-webster.com/dictionary/treen) (“of, relating to, or derived from trees”), they plucked arboreal from the Latin arboreus, meaning “of a tree”; its ultimate root is arbor, meaning “tree.” That root [arborized](https://www.merriam-webster.com/dictionary/arborize)—that is, branched freely (to use the term figuratively): English abounds with largely obscure words that trace back to arbor, meaning “tree.” Generally synonymous with arboreal are [arboraceous](https://www.merriam-webster.com/dictionary/arboraceous), [arborary](https://www.merriam-webster.com/dictionary/arborary), [arboreous](https://www.merriam-webster.com/dictionary/arboreous), and [arborous](https://www.merriam-webster.com/dictionary/arborous). Synonymous with arboreal specifically in the sense of “relating to or resembling a tree” are [arborescent](https://www.merriam-webster.com/dictionary/arborescent), [arboresque](https://www.merriam-webster.com/dictionary/arboresque), [arborical](https://www.merriam-webster.com/dictionary/arborical), and [arboriform](https://www.merriam-webster.com/dictionary/arboriform). [Arboricole](https://www.merriam-webster.com/dictionary/arboricole) is a synonym of arboreal in its “inhabiting trees” sense. (The influencers may have overdone it a bit.) Arboreal is far more common than any of these, but other arbor words also have a firm hold in the language: [arborvitae](https://www.merriam-webster.com/dictionary/arborvitae) refers to a shrub whose name translates as “tree of life”; [arboretum](https://www.merriam-webster.com/dictionary/arboretum) refers to a place where trees are cultivated; and [arboriculture](https://www.merriam-webster.com/dictionary/arboriculture) is the cultivation of trees. And of course we can't forget [Arbor Day](https://www.britannica.com/topic/Arbor-Day), which since 1872 has named a day set aside for planting trees. Despite its spelling, however, the English word [arbor](https://www.merriam-webster.com/dictionary/arbor), which refers to a garden shelter of tree boughs or vines twined together, has a different source: it came by way of Anglo-French from the Latin herba, meaning “herb” or “grass.”