Although/while – A former student recently asked me about this combination. There isn’t, as far as I can tell, a hard and fast rule on when to use each of these terms, but there may be preferred usage, and that’s what I’ll explain here. “Although” tends to mean “in spite of the fact that.” According to Mignon Fogarty, also known as Grammar Girl, “although” is called a concessive conjunction, which means that it expresses a concession. For example, Although he admits he saw her in the crosswalk, he drove through the intersection anyway.
“While” can also mean “in spite of the fact that,” but it can also mean “at the same time.” The same sentence with the word “while” instead of “although” now has one of two different meanings. While he admits he saw her in the crosswalk, he drove through the intersection anyway. In that construction, the sentence could mean that in spite of the fact that he saw her in the crosswalk, he chose to keep driving through the intersection. This sentence might imply some indifference on the driver’s part, which may (or may not) matter to the meaning of the sentence. This same sentence could also mean that at the same time that he saw her in the crosswalk, he drove through the intersection. Perhaps there’s less driver indifference with that construction. “While” meaning “at the same time” is more clearly illustrated in this sentence: While Patrick raked the lawn, I cleaned the windows. In that sentence, the reader more clearly gets the sense that Patrick and I are each doing two separate tasks at the same time.
The difference between “although” and “while” may be slight, but when you’re striving for precision in your writing, you might be wise to choose “although” when you’re making a concession and “while” when you really mean “at the same time.”
Assure/Insure/Ensure – “Assure” means to make someone comfortable or confident about something. She assured him that she would finish the project tomorrow. “Insure” and “ensure” do mean pretty much the same thing: “to guarantee or to make certain.” “Insure” is most often used when referring to insurance, as in I need to insure my new car. In older writing, there appears to be no distinction between “insure” and “ensure,” and they were–and are–often used interchangeably. Some readers, though, do insist there’s a difference, so if you’re not writing about insurance, you’ll want to use “ensure.” For example, To ensure that everyone has an equal chance to win, each person can enter the drawing only once.
Complement/compliment – “Complement” means that things go well together in some way, they complete each other, while “compliment” is to say something nice to someone else. Mike complimented Michelle on her shoes. But: Michelle’s shoes complemented her outfit. To say Michelle’s shoes complimented her outfit would be to say that Michelle’s shoes told her that her outfit was nice. You can remember the difference by remembering that if something completes something else, it complements it.
Rational/rationale – “Rational” is an adjective (a describing word, if you will) that means “based on reason or logic.” As in, Jesse’s over-the-top reaction to winning first place seems rational to me. That is, it makes logical sense to me that Jesse would have such a reaction to a first-place win. “Rationale,” on the other hand, is a noun that means “the reason or reasoning or explanation” behind something. The rationale for the smoking ban was to address the adverse health effects of second-hand smoke.
A post today on The Huffington Post covers some more commonly confused words, including moot/mute and gauge/gage, two other sets I’ve seen misused.