Rorschach Mark, also known as a Rorschach Test, is a psychological test used to measure a person's personality characteristics and emotional functioning. It is based on the inkblot test developed by Swiss psychiatrist Hermann Rorschach in 1921. The test consists of 10 inkblots that are presented to the subject one at a time. The subject is asked to describe what they see in each BLOT. The responses are then analyzed to determine the subject's personality traits and emotional functioning. The term 'BLOT' is the four letter answer to this crossword puzzle, and is an appropriate description of the Rorschach Mark.