From Psychology Wiki

Fixation has a number of meaning in psychology:

Fixation in a general sense, in human psychology, refers to the state where an individual becomes obsessed with an attachment to another human, animal or inanimate object. eg fixation to intangibles (i.e., ideas, ideologies etc.) can occur (see zealotry and fanaticism).

Fixation (Freudian). In psychoanalysis it has a more technical meaning relate to the psychosexual stages of development. If a person did not receive appropriate gratification during a specific stage, or that a specific stage left a particularly strong impression, that person's personality would reflect that particular stage throughout their adult life.

Fixation in vision (visual fixation) refers to maintaining the gaze in a constant direction. Humans (and other animals with a fovea) constantly alternate saccades and visual fixations. For example, in reading or speed reading, fixation refers to the human eye focusing upon an artifact of printed text such as white space or a word. A human being reads by fixating his eyes from one artifact to the next. Visual fixation is never perfectly steady: fixational eye movements occur involuntarily.

Gene fixation in population genetics occurs when the frequency of a gene reaches 1.

Synonyms: obsession, immobilization, adhesive (n.)