Rollo - you answered a question for us on this crossword and from your answer we realised that our Chambers was seriously out of date! The answer was a 10-letter word which was a 'group of North American Indian languages' - we've now bought a new Chambers but cannot remember what the word was! Can you help us again?
sedge47 - thank you very much for your help - have now been able to check that our new 11th edition Chambers does contain the word - lesson learned - don't rely on an 18 year old dictionary! Dongo