Flight.

To trip, perchance to fly.

Dear Word Detective: It has been bothering me for days now — what is the origin of a “flight” of stairs? I asked a friend of mine, who was stumped, and suggested that I contact you. I really hope that you can tell me, so it will not keep me up at night. I know, I know, I have too much time on my hands. — Carrie Geiger.

Well there’s no accounting for what keeps people up at night, but you might want to pick a different obsession. As soon as you solve this “flight” question, you’ll think of another weird word usage, then another, and another after that, keeping you awake into the wee hours ad infinitum. Trust me — I’ve been doing this column for nearly 15 years and I pretty much stopped sleeping around year eight. Incidentally, there’s some really strange stuff on TV at 4:30 am. I don’t think I want to know who’s watching the Teletubbies at that hour.

For a word that describes something human beings can’t do without mechanical help, “flight” has developed a wide variety of meanings, from the literal act of flying to a collection of things that fly (e.g., a “flight” of geese) to a burst of mental activity (“flight of fancy”). The root of “flight” is the prehistoric Germanic “flukhtiz,” which also gave us the verb “to fly” as well as “fly,” the small annoying insect. (“Fly” was originally applied to any sort of flying insect, which explains its presence in, for instance, “butterfly.”)

In the case of a “flight of stairs” meaning a series of steps between landings, the usage dates back to the beginning of the 18th century, and may well have been a borrowing of the French phrase “volee d’escalier.” As defined in the Oxford English Dictionary, a “flight” in this sense is “a series of steps, terraces, etc., ascending without change of direction,” but in common usage today “flight” often simply means the stairs between two floors of a building.

“Flight” in the “stairs” sense is a metaphorical application of “flight” meaning “a journey through the air for a given distance” (as in “Bob slept through the flight to Boston”). After all, climbing a “flight” of stairs is flying in a certain sense — you are traveling through vertical space, perhaps not as gracefully as a swan, but getting there nonetheless.

Interestingly, “flight” meaning “the act of running away” (as in “flight or fight response”) is completely unrelated to “flight” in the flap-your-wings sense, and comes from the Old English “flyht,” closely related to “flee.”