Big Five Personality Traits: These are five broad dimensions used by some psychologists to describe human personality. They include openness, conscientiousness, extraversion, agreeableness, and neuroticism.
Personality Inventory: This is a type of questionnaire designed to reveal the respondent's character or psychological makeup.
Factor Analysis: A statistical method used to describe variability among observed variables in terms of fewer unobserved variables called factors. In psychology, it's often used in developing tests and identifying clusters of behaviors.