The Grammarphobia Blog

Once upon a time

Q: Any advice about “on” and “upon”? People seem to prefer the ubiquitous “upon” in a sentence like “Success depends on/upon education.” Are these two alternatives equally acceptable? Or is one ever preferred over the other?

A: The preposition “upon” began life around the year 1200 as a compound of “up” and “on,” according to the Oxford English Dictionary. However, the “up” part of the meaning is all but nonexistent. Here’s how the OED explains it:

“Originally denoting elevation as well as contact, the compound has from the earliest period of its occurrence so far lost the former implication, that is, it has been regularly employed as a simple equivalent of on, in all the varieties of meaning which that preposition has developed.”

The use of “on” or “upon,” according to the OED, “has been for the most part a matter of individual choice (on grounds of rhythm, emphasis, etc.) or of simple accident, although in certain contexts and phrases there may be a general tendency to prefer the one to the other.”

Thus as far as correctness goes, the choice is yours.

But not so fast. Garner’s Modern American Usage (3d ed.) argues that “upon is a formal word appropriate for formal occasions.”

“Although some will argue that the two are interchangeable and the choice is just a question of euphony, rarely will upon prove more euphonious or natural,” Garner’s adds. “On is the shorter, simpler, and more direct preposition.”

We generally agree with that. But we wouldn’t go so far as to begin a child’s bedtime story by saying “once on a time.”

In fact, the conventional opening, “once upon a time,” has been a storied part of the English language since Chaucer’s day.

Buy our books at a local store,, or Barnes&