what is protien?

It's spelled protein.

There is a good short defintion here:
http://www.thefreedictionary.com/protein

You should also look up "amino acids", which are the building blocks of protein macromolecules.

protein

Protein is a macronutrient that plays a crucial role in the growth, repair, and maintenance of our body tissues. It is made up of smaller units called amino acids, which are the building blocks of protein. Our body needs protein for a variety of functions, including the formation of muscles, bones, skin, and organs, as well as the production of enzymes, hormones, and antibodies.

If you'd like to learn more about protein, one effective way would be to consult reliable sources such as textbooks, scientific journals, or websites that specialize in nutritional information. These sources can provide detailed information on the structure, types, functions, and sources of protein. Additionally, speaking with a registered dietitian or nutritionist might also be helpful in understanding protein and its role in a balanced diet.