The Eskimos may—or may not—have many words for “snow,” but we English speakers certainly have a number of words to describe ways to exit various conveyances.
It’s not enough, apparently, to just say you are “getting off the train.” No, some of us “detrain”—which sounds a little like something an Olympic athlete does after overtraining.
English tends to enjoy a sense of symmetry—for many actions there’s an opposite word (enter/exit) or prefix to “un-” or “de-” do it (balance/unbalance; activate/deactivate). Not so with getting on or off modes of transportation. As you walk down the jetway after a flight, you’re “deplaning.”
But: before the plane has been loaded with passengers, the gate agent never says it’s time to “plane.” No, it’s time to “board.” So why don’t we “deboard” or “unboard”? When you “board” a ship, it’s at the “embarkation” point. When you get off the ship, you “disembark.” (The New York Times Manual of Style and Usage thinks that’s a bit redundant—“why put people aboard (with the em- prefix) only to walk them down the gangway (dis-) again?”—and offers “debark” as an option, but that sounds like something an owner does to a noisy dog. )
You “board” a bus, too, but you “get off” or “exit.” The police are particularly fond of “exit”—no one ever leaves; he “exits” the vehicle or the premises (euphemisms and vague descriptions at that). Most people would say they “get out” of a car or “leave” a house.
One of the more curious members of this family is “depart.” The planes, trains, and automobiles all “depart.” Yet when they arrive, not one “parts.” In fact, when one “parts” from another, one is leaving. So why do we even need “depart”? Why can’t the train just “part” from the station?
Many of those words are useful, of course, because to say that someone “deplanes” or “detrains” tells a reader what object is being left as well as the act of leaving. But they all have a somewhat bureaucratic feel to them, as if an efficiency expert did a smashup of words to save money. It’s almost a throwback to when reporters filed by telegraph and had to pay by the word, leading to such coinages as “Unsaid when returning” and “downplay story.”
Sorry, but there’s no greater lesson here beyond that. But if you’re still on board, it’s time to simply get out.