Q I am interested in the word “decimate.” Where does it come from? – C.S., Hillsdale, Mich.

A: “Decimate” has its roots in a particularly nasty practice of the Roman army. Any Roman soldier who pondered mutiny had good reason to think twice. A technique to keep mutinous units in line was to select one-tenth of the men by lot and execute them, thereby encouraging the remaining nine-tenths to follow orders. The Latin verb for this presumably effective punishment was “decimare,” literally “to take the tenth of.”

The old Roman practice has not continued into modern times, of course, but its memorable ferocity has given us the verb “decimate,” which has been used in English since 1600.

“Decimate” was originally used in historical reference to the Roman disciplinary procedure, but it soon came to be used more broadly in what is now its usual sense, “to destroy a large part of,” as in “the bombing decimated the city” or “the plague decimated the population.” Although it carries no suggestion of “one-tenth” (despite the insistence of a few commentators that it should), the modern “decimate” does retain clearly the overtones of extreme violence and terror associated with the original sense.

Q Recently I encountered the word “duende” in my reading. The author used it to refer to a kind of charm given off by a performer. What’s the back story behind this word? – S.H., Reno, Nev.

A: The word “duende” comes from Spanish, where it translates literally as “ghost” or “goblin,” and is believed to derive from the phrase “dueno de casa,” which means “owner of a house.” The term was originally used in flamenco music and other art forms to refer to an often elusive mystical or powerful force given off by a performer. A person who is performing with duende is able to captivate his or her audience with a seemingly magical spirit that infects the music and leaves those in the performer’s presence mesmerized.

The Spanish poet Federico Garcia Lorca wrote in his essay “Teoria y Juego del Duende” (“Play and Theory of the Duende”) that duende “is a power and not a behavior a struggle and not a concept.” A Boston Globe columnist named George Frazier is often credited with introducing the word into English in the 1960s. The term has expanded in usage since that time, and nowadays appears in a broader range of contexts to refer to any kind of unspoken charm or allure (such as that given off by an athlete or public speaker).

Q Which is correct, “waiting in line” or “waiting on line”? – J.K., Albany, N.Y.

A: Both are correct – the one that you use depends mainly on where you happen to have grown up. Most Americans are far more likely to say “in line” than “on line,” but people who live in or near New York City show the opposite preference.

Exactly how and when this difference in usage originated isn’t known. Commentators on language first took note of it in the late 1950s. Examples of “on line” have since been recorded in many parts of the country, but there’s no doubt that New York City is still the place where it’s most at home.

This column was prepared by the editors of Merriam-Webster’s Collegiate Dictionary, Tenth Edition. Readers may send questions to Merriam-Webster’s Wordwatch, P.O. Box 281, 47 Federal St., Springfield, Mass. 01102.