Work is an episode of doing with a defined output. Work is characterized entirely by what it produces, not by what happens inside it. The output may be an artifact, a judgment, a transformed state, or a report that nothing was found — but it must be something nameable. An episode of doing that produces nothing nameable is not work; it is time spent.

This is the base concept. All organized activity is work when it has a defined output. The four types of work — process, procedure, derivation, and inquiry — are specializations based on what is known going in. Work that has a documented, repeatable method is skillful work. Work that does not yet have a method is ad-hoc — it may become skillful when someone writes down how to do it.

A work unit is a concrete instance of work: it names what it acts on (domain), which aspect changes (affected), how the change is produced (operation), and the specific values that make this instance distinct from other instances of the same operation (parameters). A work unit without parameters is a template, not an instance.

Work composes. A workflow is a set of work units with the constraint that the initial input type equals the final output type — the workflow takes something of type X and produces something of type X. A task is a named planning container for work units with a completion condition. Workflows are algebraic (they compose); tasks are organizational (they group work for planning and tracking).

Work is the thing that practice does and method governs. Practice without work is idle; method without work is shelfware; work without method is improvisation; work without practice is a plan that never executes.