Activity

Generally this refers to a specific type of work.  Most organizations define a list of activities that cover all of the work performed by their staff, organized by category, department, etc. This may also refer to a 3-digit code that references such an activity.

In some cases it also refers to a block of work that defines the activity\, worker\, location\, start time\, end time\, duration (may include deducted time for breaks)\, and other data pertaining to the activity.  This is also sometimes referred to as an "activity block" or a "punch" in some instances.