Vegetarianism is a part of many religious beliefs throughout the world (Seventh Day Adventist, Buddhism, Hinduism, etc).  Vegetarian sources of proteins include nuts, seeds, dried peas and beans/legumes, nut butters (e.g., almond butter, peanut butter), and soy products like soy milk, tofu or tempeh. 

Lacto-vegetarians consume dairy products, but avoid eggs and meat of any kind. 

Lacto-ovo vegetarians consume both dairy products and eggs, but still avoid all kinds of meats. 

Vegans avoid use of all animal products, including honey and leather-based products, but not all vegans follow such a strict interpretation of the diet.