Let's start with the Meaning.

What is Psychology? whenever we hear this word we often think about crazy people, people who is mentally ill and a lot more. Buts lets talk about the real meaning of Psychology.

• The word "psychology" is the combination of two terms - study (ology) and soul (psyche), or mind. The derivation of the word from Latin gives it this clear and obvious meaning.
• The study of the soul or mind.
•  The science that deals with mental processes and behavior.
• Psychology is the study of the mind, along with such aspects of mind as perception, cognition, emotion, and behavior. 

In Short Psychology is the study of mind, behavior, emotion and mental process.