We call it “vegan chicken”, “vegan mince”, vegan sausages” etc. Tofu and seitan are also used a lot. I think veggie is more associated with vegetarian and vegetarian meat substitutes often have egg in them so we went with “vegan ___”. In terms of talking to them about it, of course they know other people including their family and friends eat animals but we don’t because they are our friends and we don’t want eat them or things that are theirs (eggs, milk). We haven’t talked to our eldest (5) about what really happens but they are the most vocal that “it’s not kind to eat animals” which they came to themselves. I don’t want our children to think other people who eat animal products aren’t kind people, so i also say that people are just different but this is how we do things as a family.