Educators and policymakers advocate the need for developing engineering literacy among school students, yet there is an ongoing debate related to the conceptualization of the ‘Nature of Engineering’ (NOE) and the heuristics that should be applied. Thus, the goal of this chapter is to provide a theoretical ground for a nuanced conceptualization of the NOE while drawing on aspects of the Nature of Science through the application of the Family Resemblance Approach. We review and discuss current studies on school engineering education and the integration of engineering into the science curriculum. We describe four aspects of engineering fields: Structures, Machines, Materials, and Data, each uniquely characterized by the technology used and the artifact produced. Focusing on the cognitive-epistemic domain as defined by the Family Resemblance Approach, we describe the NOE through four categories: Aims & Values, Engineering Practices, Methods & Methodological Rules, and Engineering Knowledge, which can guide the integration of engineering education in schools.