IME I've never had an eastbound transatlantic flight on any carrier (that I can recall) where I have not been served something called "dinner".

I would check the web site. From a quick search on a random oneway booking, the answer is:

Flight: CO54
Aircraft: Boeing 767-200
Fare Class: Economy (H)
Meal: Dinner


CO tends to be conservative in the "Meal" section. "Snack" sometimes means something more, but not (rarely?) the other way around.