sadeye
" I think it’s not an absolute term, but one where there are many shades of grey.
Sorry, but No! It is an absolute term! Words mean things. You are vegetarian or you're not. Nobody cares if you're not, but don't make life difficult for the rest of us!"
Trouble is - which absolute term about vegetarianism do you want to be absolute about?
Vegetarian society defines vegetarianism as not eating: "This includes meat, poultry, fish, shellfish, insects, by-products of slaughter* or any food made with processing aids created from these."
But if you read the Oxford English Dictionary, it defines a vegetarian as someone who "A person who does not eat meat or fish, and sometimes other animal products". Now as you say, words mean things and meat specifically refers to the "flesh of an animal". So according to the Oxford English dictionary, you could eat gelatine or cochineal and still completely fulfill the dictionary definition of a vegetarian.
Of perhaps, the Cambridge dictionary definition, which again only says vegetarianism is "a person who does not eat meat". Again, no reference to gelatine, or cochineal. Interestingly, this time no reference to fish or shellfish either (although I think it is covered by meat).
But go back a few years, and Webster's 1913 dictionary defines a vegetarian as someone who "holds that vegetables and fruits are the only proper food for man." I'm guessing they don't eat pasta either!
So whilst you may be clear that a vegetarian is someone who eats no meat, no fish, no by products of slaughter. There are others who quite legitimately define vegetarian in a very different way, and will happily eat fish, but not meat, or will not eat meat but will eat gelatine etc... All of these are techincal definitions of vegetarian, depending on which definition of vegetarian you use!
And that's before you even begin to think about Ovo or lacto (or both) vegetarians etc...
So Yes, I would definitely say it is shades of grey. Perhaps that's why the Vegetarian society itself says "There are different degrees of vegetarianism". Its not so absolute after all.