"Multi Perspective Enterprise Modelling" (MEMO) is a method to support the development of enterprise models. It suggest a number of abstractions which allow to analyse and design various interrelated aspects like corporate strategy, business processes, organizational structure and information models. Any of those views can be modelled with a specific modelling language or diagram technique respectively. In order to allow for a tight integration of the various perspectives, the modelling languages suggested by MEMO are based on common concepts. Those concepts are defined within a common meta-metamodel. Each of the languages within the MEMO framework can be regarded as a specialised language/ terminology to serve the purpose of specific tasks. One of those tasks is the design of information systems. For this purpose MEMO suggests an object-oriented approach. The corresponding language, MEMO-OML (MEMO Object Modelling Language), is intented to support analysts and designers of information systems. In the current version, it is mainly restricted to the description of static aspects. MEMO-OML provides concepts which are suited to cover a large part of the software lifecycle. The concepts are specified in a semi-formal way with a graphical metamodel. It defines the abstract syntax and semantics of MEMO-OML. Additionally, a graphical notation is introduced. The metamodel is supplemented by comprehensive discussions of various language features.