Metamudel on mudeli mudel. Sõltuvalt rakendusest võib metamudelil olla erinevaid määratlusi: metamudel on
loogiline infomudel, mida kasutatakse modelleerimisel samas (või erinevas) tähenduses elementide eritlemiseks (A logical information model that specifies the modeling elements used within another (or the same) modeling notation. (IEEE 1175.1-2002 (R2007) IEEE Guide for CASE Tool Interconnections-Classification and Description, 3.8))
vaade objekti alamhulga konstruktsioonidele, mida väljendatakse nende konstruktsioonide abil nii, et eksisteerib kehtiv metamudeli eksemplar, mis on metamudeli enda kirjeldus (A metamodel Vm for a subset of IDEFobject is a view of the constructs in the subset that is expressed using those constructs such that there exists a valid instance of Vm that is a description of Vm itself." (IEEE 1320.2-1998 (R2004) IEEE Standard for Conceptual Modeling Language Syntax and Semantics for IDEF1X97 (IDEFobject), 3.1.111))
mudel, mis sisaldab mudeli ülekandeks vajalike metaentiteetide, metasuhete ja metaomaduste määratlusi (A model containing detailed definitions of the meta-entities, meta-relationships and meta-attributes whose instances appear in the model section of a CDIF transfer. (ISO/IEC 15474-1:2002 Information technology -- CDIF framework -- Part 1: Overview, 4.2))
mõistete, seoste ja reeglite täpsustus, mida kasutatakse metoodika kindlaksmääramisel (Specification of the concepts, relationships and rules that are used to define a methodology. (ISO/IEC 24744:2007 Software Engineering--Metamodel for Development Methodologies, 3.4))
mudel, mis määratleb modelleeriva keele mõisted ja nende seosed (Model defining the concepts and their relations for some modeling notation. (ISO/IEC 15909-2:2011 Software and system engineering -- High-level Petri nets -- Part 2: Transfer format, 4.1.6))