What's the difference between a crevice and a crevasse?

Crevice and crevasse are very similar words: both come from Old French crever "to break or burst" and both refer to an opening of some kind. In fact, you can say that the only notable distinction between the two is the size of the openings they denote—and that one of them—crevice—is far more common than the other.

A crevice is a narrow opening resulting from a split or crack. In nature, crevices exist mostly in rocks and cliffs, but writers sometimes use the word for similar openings found in other materials, as in "crumbs in the crevices of the cushion." The word also is used metaphorically, as in "the cracks and crevices of memory."

Crevasse refers to a deep hole or fissure in a glacier or in the earth. In most instances, the word appears with enough context that the depth of the opening is easy enough to figure out, as in "a climber who fell 30 feet into a crevasse."

You'll sometimes find crevice used where crevasse is expected—probably because it's the word people are more familiar with. One way to remember the distinction between crevice and crevasse is that the i in crevice, the smaller hole, is a thinner letter than a in crevasse, the larger hole. Or, should you step into a crevasse, perhaps you'll have time for a lot of "Ahhhs"?