A data model organizes data elements and standardizes how the data elements relate to one another. Since data elements document real life people, places and things, and the events between them, the data model represents reality. For example a house has many windows or a cat has two eyes.
A data model explicitly determines the structure of data. Data models are specified in a data modelling notation, which can be graphical in form.
A data model can be sometimes referred to as a data structure, especially in the context of programming languages. Data models are often complemented by function models.
Source: Center for Data Analytics and Reporting, Princeton University https://cedar.princeton.edu/understanding-data/what-data-model