梦幻 (mèng huàn) is a noun meaning a dreamlike, illusory state, often used poetically or figuratively (e.g., 梦幻般 'dreamlike'). It differs from 幻想 (fantasy/daydream, implying active imagination), 幻觉 (hallucination, a sensory misperception), and 幻影 (phantom/mirage, a visual apparition). 梦幻 is broader, describing a quality rather than a specific type of illusion.