Desultory. Circus riders in ancient Rome jumped from one horse to another during their acts, which led to their being called desultors, or leapers, from the Latin salire, "to leap." They were soon compared to people who fitfully jump from one idea to another in conversation, which resulted in the word desultorious, "to be inconsistent, aside from the point," the ancestor of our English word desultory.
Fata Morgana. Mirages of houses, ships and mirror images, often seen in the water as well as in the air, and often doubled -- inverted above each other -- have frequently been reported in the Strait of Messina and other places. They are named Fata Morgana after Morgan le Fey, a sorceress in Arthurian legend, the words Fata Morgana being an Italian translation of Morgan le Fey.
Paeans; peony. The gods wounded in the Trojan War were cured by the physician Paean, according to Greek mythology. Thus many plants once prized for their curative powers were named for Paean, including the flower called the peony. Because they believed their god Apollo often disguised himself as Paean, the Greeks sang hymns of thanks and tribute to him that came to be called paeans, these the source for our paeons of praise.
To buttonhole. "Barricade your doors against the button-holding world!" a British magazine warned its readers over a century ago. Button-holding, "grabbing a man by the top button of his coat and holding on with all the strength of the boring until you sell him one thing or another," was so common in the 19th century that button-holder was defined in many dictionaries as "one who takes hold of a man's coat by the button so as to detain him in conversation." People must have been button-holding and wearying people in France, too . . . for the French had a similar phrase. In those days men's coats had buttons all the way up to the neck, including one on the lapel that could be buttoned in cold weather. When fashion decreed that upper buttons be eliminated, button-holders didn't suddenly reform. Instead, they began grabbing people by the buttonholes designers (for no good reason) left on the lapels, and the phrase became to buttonhole.
Every Thursday you'll find word and phrase derivation stories here. If you're just discovering the blog, click on "phrase origins" in the tags below to see other derivation posts. I haven't been doing them for long, but they'll pile up soon enough -- because I don't intend to stop.