A workshop is

Concept: Names for group learning events are distinguished not by their subject matter but by three structural axes — how large the group is, how long and how intensively the event runs, and what the participants actually do (listen, talk, or practise). A description that fixes only the activity names a broad category of gathering; a description that fixes all three axes names a specific training format.

Application: The term in the stem denotes a short, high-intensity programme run for a small group in which the participants work hands-on to build a skill or technique aimed at a specific problem. All three axes are fixed at once — small group, brief and intensive, practice-oriented — so the matching description is "a brief intensive course for a small group emphasizing the development of a skill or technique for solving a specific problem".

Cross-check — the remaining descriptions fix fewer axes, or fix them differently:

• "a meeting for discussion on a topic" fixes only the activity, that is talking; group size, duration and intended outcome are all left open, which makes it the most general description of any assembly convened to deliberate.

• "a conference for discussion on a topic" adds formality and scale to that same activity: a large, usually multi-session gathering built around presentations and discussion, with no practice component.

• "a class at a college or a university in which a teacher and the students discuss a topic" fixes the setting, namely an institution’s curriculum, and fixes who leads, namely a teacher, while the activity itself remains discussion.

Result: the description that simultaneously fixes a small group, a brief and intensive duration, and hands-on skill development for a specific problem is the one that matches the term.