GUEST,Shimrod

It occurs to me that the word 'book' means the same today, in 2009, as it did in 1954 - or do we have to re-define every word in the dictionary because most of them were coined in the past? How old does a word or term have to be for it to become out-dated?

I was under the impression that dictionaries derived their definitions from the spoken language not the other way round and, yes, dictionaries are updated as usage changes. I don't think there are any other words in general use apart from "folk" that have had their meaning defined by a committee.