This chapter proposes a broad framework for understanding mechanisms across different scientific fields, drawing on Illari and Williamson’s (European Journal for Philosophy of Science 2, 119–135) minimal definition of mechanisms. While mechanistic reasoning has gained prominence in science education research, discussions have primarily focused on specific domains, particularly the life sciences and chemistry. The chapter addresses this gap by examining how mechanisms can be characterised broadly across disciplines while maintaining their essential elements: what a mechanism does, what it is made of, and how it operates. By exploring three diverse phenomena—thermal gas expansion, seasonal daylight variation, and photosynthesis—the chapter demonstrates how different scientific phenomena can be understood through a common mechanistic lens, despite their distinct characteristics. The framework reveals that mechanisms share fundamental features that can guide mechanism discovery and explanation across fields. This broader perspective aims to contribute to ongoing discussions about how to examine, characterise, and guide students’ mechanistic reasoning in specific domains while acknowledging the unique characteristics of mechanisms across different scientific fields.