Digital BW, The Print

There was a discussion on the List recently about "metamerism".  At 
the time, I was unfamiliar with this word but thought I had gotten 
the gist of it's meaning from the context of the posts, such as this 
one from Jeff M.:

>All things in life will look slightly different under different 
lighting conditions... and these inksets reflect that. If you try and 
print a grayscale image using Epson color OEM inks... then you will 
see METAMERISM. The print totally changes color under different light 
sources. The Epson OEM inks are so bad with metamerism that I find it 
an obstacle even for color images.<

Well, I finally got around to pulling out the dictionary a few 
moments ago and now I'm thoroughly perplexed.  I'm guessing that I 
need a better dictionary because my copy of the American Heritage 
Dictionary defines metamerism as: "The condition of having the body 
divided into metameres".  Ok.....well then, it goes on to define 
metamere as: "One of a series of homologous body segments, as in 
worms and lobsters".

Anyone got a better definition of metamerism at hand?  Maybe from a 
complete set of the Oxford English Unabridged Dictionary 20+ 
volumes?  American Heritage just doesn't cut the mustard.  ;-)

Gary Benson
Eagle River, Alaska