A good bit of the confusion in the psychoanalytic literature surrounding the terms "psychic content," "process," "function," and "structure" results from unclear definitions. The author suggests that "psychic content" be defined as the items of our experience. A psychic process is a sequence of psychic acts or events that has some impact on psychic content. A psychic function is the goal-oriented outcome of the action of organized psychic processes. Psychic structure is often thought of as organized, patterned, enduring sequences of mental events, but this definition is a static one. A dynamic definition more in keeping with the way "structure" is used by the structuralists would seem to be better: a "psychic structure" is any organized group of mutually related psychic contents and/or processes which carries out a specific function. Some problems arising from the unclear use of these four terms are discussed.