I’m writing a document aimed at the US market, and am unsure whether I should use “insure” or “ensure” to mean “guarantee”. In UK and Irish English, we use “ensure” (and we use “insure” only when it comes to monetary guarantee). Webster’s tells me it’s interchangeable, but most US-based documentation I’ve read uses “insure” for this purpose.
Any US dopers care to enlighten me?
Those who care about strict usage follow the UK practice you’ve described. While they are interchangeable in the U.S., it’s useful to make a distinction between the two words.
I use “insure” only when speaking of monetary guarantees as well, and I believe that’s the proper usage:
“The pipeline will ensure a steady supply of oil for years to come.”
“The company will insure the pipeline against losses causes by breaks.”
“The company will assure the public of the continued safety of the pipeline.”
I would also add that in my profession (insurance and law), the two are not interchangeable, ever, because “insure” has a specific meaning in that context (“to purchase an insurance policy for”).
That’s 100% of this very small sample, so I’ll go with the “more precise” version.
Thanks for your help.
I would definitely not say that they are interchangeable in the U.S. To insure means only to indemnify someone against loss, i.e., to promise payment in the event of a loss, in consideration of premium. To ensure is to guarantee that something gets done or that something happens, whether the guarantor does it himself or gets someone else to do it.
Roughly speaking:
“Ensure” - to make certain something happens.
“Insure” - to protect against something bad happening.
Yeah but… almost all the publications I read that emanate from that great country use the “insure” spelling.
ensure.
Ditto – ensure. I think Webster’s calls them interchangeable because we yanks screwed up the language. Language is defined by its usage, after all.
I detest seeing “insure” in lieu of “ensure” because there is a difference, but not everyone knows that and we conform ourselves with what is used, I suppose.
AP style insists on the “insure refers only to insurance” definition, not interchangeability.
Editor checking in. Insure refers only to insurance here in the U.S. Or should, anyway. Assure/insure/ensure usage was a pet peeve of an old boss.
Thanks, everyone. It’s nice to get this cleared up, anyway, because though I can (just about) write in the American style, that particular word usage sets my teeth on edge. And it will no longer.
Don’t get me started on using myriad as a noun. I recently looked it up on dictionary.com and discovered that it now is a noun as well as an adjective.
I have no idea how long this has been the case. The last time I looked up myriad was circa 1983…
I might just have to action that. 
I can sympathize. The Usage Panel now allows “aren’t I?” We’re going to hell in a handbasket, isn’t we?
What would you use instead? “Ain’t I?” or “Am I not?” (in Ireland, some people say “Am’nt I”, which is more logically correct, though it sounds weird to me)?
I’m not sure whether it is comforting or not to see all these replies saying that “insure” is a monetary guarantee in the US, because I never hear people say “ensure”. I’m a Brit who has lived in the US for six years and I doubt I’ve ever heard an American say “ensure”.
Mind you, here in Georgia it’s probably hard to tell which word they are saying: the “en” (or “in”) would be two syllables on its own.
I may regret asking, but how do you use “myriad” as a noun? The Great Myriads of Giza? What?
Instead of saying “myriad widgets” it would be “a myriad of widgets.”