환상 (Illusion) refers to a perception that does not match reality. It can occur in various forms, such as visual, auditory, or tactile experiences. Illusions often trick the brain into interpreting sensory information incorrectly, leading to a distorted understanding of the environment. In psychology, illusions are studied to understand how the mind processes information. They can reveal insights about human perception and cognition. Common examples include optical illusions, where images appear different from what they truly are, and auditory illusions, where sounds are misinterpreted. Understanding illusions helps in fields like neuroscience and art.