PS, P.S., ps, and other variants may refer to:
Psychology is the science of behavior and mind, embracing all aspects of conscious and unconscious experience as well as thought.
Psoriasis is a long-lasting autoimmune disease which is characterized by patches of abnormal skin. These skin patches are typically red, itchy, and scaly.
Psychopathy, sometimes considered synonymous with sociopathy, is traditionally defined as a personality disorder characterized by persistent antisocial behavior, impaired empathy and remorse, and bold, disinhibited, egotistical traits.
Pseudoscience consists of statements, beliefs, or practices that are claimed to be scientific and factual in the absence of evidence gathered and constrained by appropriate scientific methods.
Psychosis is an abnormal condition of the mind that involves a loss of contact with reality. People experiencing psychosis may exhibit personality changes and thought disorder.
Pseudomonas aeruginosa is a common Gram-negative, rod-shaped bacterium that can cause disease in plants and animals, including humans.
The Book of Psalms (Hebrew: תְּהִלִּים or תהילים, Tehillim, "praises"), commonly referred to simply as Psalms or "the Psalms", is the first book of the Ketuvim ("Writings"), the third section of the Hebrew Bible, and a book of the Christian Old Testament.