Psychology (noun)

1. The scientific study of the human mind and its functions, especially those affecting behavior in a given context.
2. The mental characteristics or attitude of a person or group.

Origin:

Mid 19th century from psychology, from the greek psykhe- meaning soul + logia meaning study of.

Examples:

1. She studied psychology in college.
2. The psychology of consumer behavior is fascinating.
3. The psychology of the criminal mind is complex.
4. The study of psychology can help us understand human behavior.
5. His background in psychology was an asset in his job as a therapist.