Martin Goldstraw over at the Cheshire Heraldry Blog had a recent post (May 9, 2010) wherein he notes his frustration at folks (in this particular instance, on Wikipedia) who persist in calling a coat of arms, or even worse, a complete achievement of arms, a "crest". His post is well worth reading. I recommend you drop on over there and give it a perusal. It can be found at: http://cheshire-heraldry.org.uk/weblog/2010/05/09/beware-wikipedia-arggghh-â-itâs-not-a-crest/
Though I will note that I myself have to try (the emphasis here is on the word "try"; I don't always succeed), try not to get too worked up over the usage; it came to me that it might be a losing battle when I discovered that the venerable old newspaper, The Times of London, which certainly ought to know better, was using "crest" instead of "arms" or "coat of arms". On the plus side, I don't recall that they called it a "family crest", but then again, my memory may not be all that it used to be. ("You know, they say the mind is the second thing to go." "What's the first?" "Umm, I forget.")
Happy New Year!
2 weeks ago