What term describes a productive activity resulting in something useful?

The term that defines a productive activity resulting in something useful is work. Work typically involves effort and a purposeful application of skills or labor to achieve a specific goal, create a product, or provide a service. This definition aligns with the concept of productivity, as work generally leads to tangible results that contribute value or utility in various contexts, whether in a professional setting or through personal projects.

In contrast, a hobby refers to activities that people engage in out of pleasure or relaxation, often without a focus on production or utility. Leisure pertains to free time spent away from work or duties, usually for enjoyment, and not necessarily aimed at producing a useful outcome. A task can also imply an activity that needs to be completed, but it may not always result in something that is broadly considered productive or useful. Thus, "work" best encapsulates the idea of an activity that is both productive and yields something of value.