0 a person who does not eat meat, fish, or dairy products (= milk or foods made from milk) but does eat eggs:
Some people are ovo-vegetarians because they are lactose-intolerant.
1 not eating or including meat, fish, or dairy products (= milk or foods made from milk), but including eggs:
We can complete it step by step however long the road is and it can't be completed however short the road is if you don't even mark your footprint.