1) Field that utilizes protein sequences, expression and structure to determine how proteins relate, interact and function in an organism; includes characterizing and cataloguing proteins and protein libraries, comparing variations in protein expression levels under different conditions, studying protein interactions and functional roles; techniques are performed in an automated, large scale manner; may also involve bioinformatic analysis and storage of data.

2) The systematic study of the complete complement of proteins (proteome) of organisms.

3) A branch of biotechnology concerned with applying the techniques of molecular biology, biochemistry, and genetics to analyzing the structure, function, and interactions of the proteins produced by the genes of a particular cell, tissue, or organism, with organizing the information in databases, and with applications of the data (as in medicine or biology).

4) The study of genes, their resulting proteins, and the role played by the proteins the body's biochemical processes.