What is the difference between a protein and peptide?

[Wisdom Seeker]

Both are made of amino acid chains, so what's the difference? I'm trying to get a definition going in my head so I differentiate between the two and all I can think of is perhaps a protein is folded and serves a structural function while amino acids are not??
This becomes even more confusing with terms like polypeptides

[Kunal Pandya]

Amino acid :- Amino acids are molecules containing an amine group, a carboxylic acid group and a side-chain that varies between different amino acids NH2-CH(R)-COOH [ Where R is side chain).Their were 20 natural occuring amino acid and they are polymerize to give Peptide,Polypeptide and protein.

Peptide Bond :-A peptide bond is a covalent bond that is formed between two amino acid when the carboxyl group of one amino acid reacts with the amino group of the another amino acid. Simply [O=C-NH ], while amide bond is [O=C-NH2]

Peptide :- Peptides are short polymers of amino acids linked by peptide bonds. Here is confusion about no. of amino acid but mostly till 50 amino acid they were called peptide or polypeptide and if no. of amino acid is more then 50 it's called protien.

Polypeptide is same as peptide which use by some of the chemist to define peptide haviny amino acid more then 2 but less then 50 .

Protein :- Having amino acid more then 50 which were linked by peptide bond

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[greatmona1]

I am same with Kunal Pandya .Thats' are main difference between a protein and peptide.Thanks.