>>>>BTW, mixing dairy and meat - does that mean you can't have mayo on your meat sandwich? Shame!
>>>>
>>>
>>>Mayo is parve, it doesn't have dairy ingredients, AFAIK.
>>
>>I'm not sure that if it doesn't contain eggs, it can be called 'mayo'.
>
>May be I'm missing something here, I always thought that mayo is an abbreviation for mayonnaise, which, AFAIK, is parve. Am I wrong and there is something else I don't know?

Depends on how you define 'parve'. I've heard it used to mean neither meat nor 'milk', in which case it's ok, but if you use it as neither meat nor 'dairy', then it isn't.

Google the words Mayonaisse and ingredients. I've never heard of mayonaisse made without eggs.