The term "meta" can refer to something that is self-referential or refers to something abstract or higher-level. It is often used as a prefix in English to create words that describe a higher level of abstraction or a second-order concept. For example, metadata refers to data that describes other data, while meta-analysis refers to the statistical analysis of multiple studies. In philosophy, "meta" is used to refer to concepts that are beyond the physical world, such as metaphysics. In general, "meta" is used to indicate that something is about itself or refers to a higher level of understanding.