Any given thing or process has its significance under many scopes. What has certain relevance for an entity (a person, institution, artifact, etc.) could be minor/trivial or far superior for others. Take for example the relative importance of Heart Transplant in Cardiovascular Surgery, then its importance in Medicine, then in Science and so on. For sure in the first environment we can expect great and detailed works on the subject, then a general knowledge in the second, and maybe just a reference or none at all in the last.
Consider now that for many large projects and organizations there is a need for creating common assets for dealing with the involved complexity. These assets could be specialized languages, standards, protocols, policies, artifacts, etc. As example we can consider the armed forces or the sport teams: They have a common language, common symbols (insignias, flags), equipment, protocolized communications and operational procedures, rules of conduct, etc. Then is required a superior entity, for understand these of complex worlds, to meet their common needs. That superior entity is on a meta or supra level: beyond that worlds.
In this case we have another perspective: The “here” (world) vs the “beyond/upon” (meta). For example: A construction team must build a house, then the architect communicates the intended design with blueprints. A meta-level here is the blueprints standard used for the purpose of building. That problem was studied and evolved since centuries and now has it common language (ie: a dotted square represents a concrete block or a door indicates its opening side with an arc). On the same example, another meta-level could be the command hierarchy of the construction company: the architect is the chief and the team are their subordinates.
Then, when trying to effectively communicate between different contexts, the data interchanged must be altered to be well understood by the intended audience. That change can be made in the form of: level of detail, vocabulary, symbols, translations, perspective and abstraction, etc. Also, the purpose must be considered: decision making, specialized work, informational, etc.