different types of vegetarians

Hello. I am a guy 19 years old and I heard that there is more than one type of vegetarians. I don't really get this, since I thought that the term vegetarian can mean only one thing - that you don't eat meat, and now I hear about some classification. Could you please explain this to me because I don't get it.

Yes, that is true. Not all the vegetarians are the same. You have total vegetarians, who eat only plants, Vegans who not only do not eat meat and anything of animal, but even don't wear anything that is of animal origin. Than you have lacto-vegetarians that eat dairy products, lacto-ovo-vegetarians that eat both eggs and dairy products. Pesco-vegetarians (this ones I do not understand) – they eat fish, which is meat, but they still call themselves vegetarians. and pollo-vegetarian – the same thing about this ones, except they eat poultry instead of fish.