Is "key" as an adjective, meaning "crucial", standard in American English?

As an adjective, key can mean "Of crucial importance" (Oxford). For example: the key facts are the most important facts, or a key worker is an employee whose role is especially vital.

In British English, key in this sense is every bit as common and well-understood as crucial would be. There are some stock phrases where it's especially familiar, but it's not limited to those; you could put it in front of any noun (say, key elephant) and, with the right context, it would make perfect sense ("the matriarch is the key elephant to protect from poachers").

Many years ago, when I was a rookie, someone much more experienced told me that I shouldn't use key as an adjective because "Americans don't understand it". I've been carrying that "fact" with me ever since then – and was just about to impart it to someone else the other day, when I paused to wonder whether it's actually true.

I can obviously see that the meaning is listed in American-centric dictionaries (e.g. Merriam-Webster), but that doesn't help me understand whether it's a common use or an obscure one. I can't find anything about it in any online American style guide but, again, that might mean it's completely uncontroversial or it might mean it's utterly obscure. And the fact the word key has so many different meanings makes it a difficult one just to Google for!

So, can anyone help please?

Solution 1:

It's a fair question, I suppose – I mean, I believe you were told what you said you were told. However, I'm having trouble imagining anyone on this side of the Atlantic who would be confused by this use of the word key.

As a matter of fact, sportswriters don't usually write for a sophisticated audience, but the Boston Globe wrote about:

Three key plays that won the Super Bowl for Patriots

and the USA Today published a story called:

Gronkowski key part of Patriots' winning Super Bowl

More recently, a sportswriter analyzed Game 1 of the NBA Finals, saying:

Rebounding is a key in any series in basketball, and that figures to be one of the biggest advantages for the Cavaliers. However, it was Golden State who won the battle on the glass, outrebounding Cleveland, 48-45.

This isn't just a sports thing, either. From a recent New York Times interview with a publishing executive:

Every opportunity is a different challenge, and I will quickly assess what the key issues are...

In short, either your friend had an erroneous perception, or else he was pulling your leg.

Solution 2:

"This is a key idea."

I learned as a child to use the expression above as a compound noun. "Key" was not an adjective, but was part of a compound noun. In recent years, I hear people saying

"This idea is key."

thus treating "key" as an adjective.

"This is the car key."

"Car" is not an adjective here, so you don't say "This key is car." Likewise "key" as I first learned it. Language changes even when we don't like it.

Solution 3:

I am from and have always lived in the U.S. and I have always understood "key" as being sometimes synonymous with crucial. Of course, I have also steeped myself in British literature from a young age so that my experience might not be truly representative of the average american. Interestingly enough, however, I ended up on this page because I was typing a paper and used key in that form, and Microsoft Word corrected me, saying that "key" could not be used in this way.

Solution 4:

I'm always astonished how tenacious the term adjective is for nouns that are part of a compond noun. I know that in English school books everything that is attributed to a noun is called adjective. A very dubious use, as adjective is a word class and no term for describing noun groups (with a noun as main element and all others things as subelements).

In the case of key term/key figure etc we have a special type of nouns, compound nouns. In "an old man" "old" is an adjective. In "raincoat" "rain" is no adjective and English grammar terminology should have a special term for describing the formation of compound nouns. I think it would be reasonable to say "rain" serves as compound element in "raincoat". To say it is an adjective is in my view a kindergarden term.