Concept formation concerns how people identify similarities and differences across experiences and construct categories. Human classification is not always based on rigid necessary-and-sufficient conditions; typical examples, context, and current goals can influence judgments.
The classification depends on the purpose
The same technologies can be grouped by material, production process, or application. These partitions answer different questions. It does not follow that only one is objectively correct for every purpose.
Abstraction also loses information
Abstraction makes comparison possible by ignoring details, but some discarded details are consequential. A shared principle across industries may fail to transfer because of temperature, scale, cost, or operating constraints.
Application to technology exploration
Representing a technology through its function, mechanism, conditions, and constraints can enable comparisons beyond shared keywords. Avoid declaring one extracted feature to be its permanent essence; try alternative perspectives.