Wiktionary
n. (context data modeling English) A map of concepts, their property, the relationships between the concepts and the properties of the relationships.
Wikipedia
A conceptual schema is a high-level description of a business's informational needs. It typically includes only the main concepts and the main relationships among them. Typically this is a first-cut model, with insufficient detail to build an actual database.This level describes the structure of the whole database for a group of users. The conceptual model is also known as the data model as data model can be used to describe the conceptual schema when a database system is implemented. It hides the internal details of physical storage and targets on describing entities, datatype, relationships and constraints.