@jozero The terminology is usually like this:
ovo-lacto (sp?) vegetarian - Doesn't eat any meat but does eat egg (products) and mil (products)
vegetarian - doesn't eat any animal products like fish or meat or sea food
vegan - doesn't eat nor use any products that proceeded from an animal, including leather, honey and the like
To the OP:
Your best bet, if not speaking Spanish, is preparing a laminated flash card stating your dietary preferences and showing it to the waiter/shop keeper. In your case (assuming ovo-lacto vegetarian) that could read:
Soy vegetariano/a, no como carne, ni panceta, ni marisco, ni pescado. Me puede recomendar algo?
I am a vegetarian. I don't eat meat nor bacon, nor seafood, not fish. Can you recommend some dish for me.
Buen Camino, SY
PS There are a 'few' Spanish vegetarians around also, so it isn't an out of this world problem ...