I'm an AE speaker, but nappies are BE for diapers, if I'm not mistaken.
Should be cloth diapers in AE.

Liz (US) you are not mistaken - "nappy"/"nappies" definitely BE, common form, not at all "cute"
Dictionary: nappy

I am aware that this is a common form when speaking, and of the Leo entry (though it does not say US for diapers). My question is whether or not there is a more formal term more appropriate for a catalogue.

So is the catalog intended for the UK? Not sure I really understand your question...
Do you mean "Is the word 'nappies' appropriate for a catalog selling cloth diapers in the UK?"

Wish I could help... don't have a feel for the work in BE.

work = word, of course

http://www.mothercare.com/invt/lv4019&bklist=
http://www.boots.com/shop/department_new_temp...
http://www.chambersharrap.co.uk/chambers/chre...

nappy (BE), no other term used for cloth "Windel"

I don't know whether there is a higher-register term for 'diaper' (AE)
'Diaper' is not used in UK.

I just noticed I wrote "US" in my orig. question. Mea culpa, it should have read UK. (time for bed?) Thanks for the helpful answers.

Selkie - Apparently your question was UK only. But just-in-case, the standard US term is "diapers". The term "nappies" is unfamiliar (except to people who are familar with BE). "Cloth diapers" is understandable, but is not the standard term. The standard term is simply "diapers".

I more or less agree with Eric, but you might need to include the cloth part with diaper(s) if they really are cloth. I would say the majority of people in the US nowadays use disposable diapers made out of plastic. I would not be surprised if there are people that do not even know diapers can be made out of cloth.

Napkins in BE are what you wipe your mouth on after a meal. The word "nappy" does come from "napkin", and you find "napkin" in some old books, but today the standard term is "nappy". The cloth ones are "terry nappies":

http://www.mothercare.com/invt/lx1500&bklist=

Is the word "serviette" no longer in use for the thing you wipe your mouth on? In Cambridge back in 1989, I asked for a napkin in a restaurant and was quickly hushed by my horrified English friends who informed me that the correct word was serviette and that I had just asked for a diaper.

Thank you for all the kind answers about US usage, but since that is where I am from, I am aware of the usages there.

@Selkie: Your Cambridge friends have a brilliant sense of humour. They certainly made me (another Cambridge man) laugh! I am sure they were just winding you up and probably had a good laugh at your expense when your back was turned. We do so enjoy teasing Americans about their use of our language.

To clarify: "serviette" is the more commonly used expression for a table napkin, but there is nothing wrong with the term "napkin" in the context of dining. What you call a "diaper" is known as a "nappy" (as has been explained here) - and the word "nappy" has long since superseded the word "napkin" from which it was once derived.

Joe W.: Well, I'm glad I finally get the joke after all these years and can enjoy a laugh at my own expense.

In NZ, napkins (or baby napkins) is still used as the formal term, and nappies is the familiar term (but clearly more common).

http://www.google.at/search?hl=de&as_qdr=all...
http://www.google.at/search?hl=de&as_qdr=all...

"Damenbinden" are also called "sanitary napkins" (not so often "sanitary towels", as elsewhere.)
http://www.google.at/search?hl=de&as_qdr=all...
http://psy.otago.ac.nz/r_oshea/FUN STUFF/oztaboo.html