What term describes the amount of time that a person is actively engaged in work?

The term that accurately describes the amount of time that a person is actively engaged in work is "Uptime." Uptime refers to the periods when an individual is productive and involved in tasks related to their job or responsibilities. This concept is often associated with efficiency and the effective use of working hours.

When discussing work-related terms, it’s important to differentiate between active engagement and other states of activity. For instance, downtime refers to periods when work is not being performed, such as breaks or system outages. Free time is typically associated with personal leisure, not work-related activities. Idle time refers to time spent with inactivity during work hours, indicating periods when the individual is not engaged in productive tasks despite being present at work.

Thus, "Uptime" is the best term to represent the concept of being actively engaged in work, highlighting a person's productivity during designated working hours.