A "work unit" is a term frequently utilized in various industries to refer to a specific task or project an individual or team must accomplish. Some synonyms for work unit include "assignment," "task," "project," "job," "duty," "responsibility," "undertaking," and "mission." Each of these terms refers to a specific task or set of tasks that must be completed as part of a larger project or objective. The term you choose to use may depend on the context in which it is being used. While "assignment" may be the right term in a school setting, "undertaking" may be the appropriate term for a large construction project.