Psychosexual Development: Freud's theory that outlines the stages of psychological and sexual development from infancy to adulthood, where the individual's personality is shaped by the resolution of conflicts at each stage.
Fixation: A state in which an individual's libido, or sexual energy, remains focused on a particular stage of psychosexual development, leading to the development of certain personality traits or behaviors.
Oral Incorporation: The tendency of individuals in the oral stage to incorporate or take in objects, ideas, or experiences through the mouth, which can lead to behaviors such as thumb-sucking, nail-biting, or excessive eating.