What are the different types of vegetarianism?

So what does it mean to be a vegetarian exactly? Well, the word "vegetarian" is actually a broad and generic term for someone who avoids meat and animal product from his or her diet. There are actually many different types of vegetarian, depending on what he includes and excludes from his diet.

Here's a list of the different types of vegetarian:

1) Lacto-ovo-vegetarian: The foods eaten include dairy, eggs, fruits, vegetables, grains, nuts, and seeds. The food not eaten include meat (red, poultry, fish). Emphasis on consuming dairy, and eggs.

2) Lacto-vegetarian: The foods eaten include dairy, fruits, vegetables, grains, nuts, and seeds. The foods not eaten include meat (red, poultry, seafood, fish), and eggs. Emphasis on consuming dairy.

3) Ovo-vegetarian: The foods eaten include eggs, fruits, vegetables, grains, nuts, and seeds. The food not eaten include meat (red, poultry, seafood, fish). Emphasis on consuming eggs.

4) Pesco/pesca - vegetarian: The foods eaten include seafood, fruits, vegetables, grains, nuts, seeds, eggs, and dairy. The food not eaten include meat (red, poultry, pork, etc.). Emphasis on consuming fish and seafood.

5) Pollo - vegetarian:  The foods eaten include poultry, fruits, vegetables, grains, nuts, seeds, eggs, and dairy. The food not eaten include meat (red, pork, and seafood). Emphasis on consuming poultry.

6) Semi - vegetarian: The foods eaten include eggs, fruits, vegetables, grains, nuts, seeds, dairy, and on occasion meat. The food not eaten include meat most of the time (red, pork, poultry, and seafood). Emphasis on consuming meat on occasion, like on Thanksgiving.

7) Vegan: The foods eaten include fruits, vegetables, grains, nuts, and seeds. The food not eaten include eggs, dairy, meat(red, pork, poultry, seafood) and all animal byproducts.  Emphasis is on not consuming any meats whatsoever.

8) Fruitarian: The foods eaten include fruits, vegetables, grains, nuts, and seeds. Fruitarian rarely eat processed or cooked foods. The food must have no part of the plant that results in the death of the plant. They do not eat meat obviously. Emphasis on consuming fruits and vegetables without the death of plants.

So you can become a vegetarian, or more specifically a semi-vegetarian, by consuming meat on an occasional basis. You can even become a semi - vegetarian by eating meat 6 days a week, and having a meatless meal 1 day of the week. So a semi - vegetarian diet is the most flexible vegetarian diet of all. A vegan or a fruitarian on the other hand, are the most strict diets as compared to the other types of vegetarian diets.

Reference:
http://www.eiu.edu/dining/files/VegetarianismII.pdf