Vegetarians vary enormously in what they are comfortable eating, so please specify your preferences in the question.
The most common U.S. definition involves abstaining from any food product that requires animal slaughter. This normally means lacto-ovo vegetarian, which, unlike vegan food, places no restriction on the consumption of other animal products such as milk, eggs, or honey.
Questions that do not specify an additional subtype of vegetarianism will normally be interpreted as lacto-ovo.
Please don't use this tag for just any food which happens to not include meat. It is supposed to be used in cases where it is important to the question that the food is vegetarian (and should stay suitable for vegetarians after a solution has been found).