From the FAQ on the Garmin website:
Garmin Connect processes the data of an activity in many ways to help you fully evaluate your activity data.
Below are the more in depth descriptions of various time and pace/speed fields:
Moving Time: includes only the time you were moving
Time: includes time moving and time not moving (if Auto Pause is off)
Elapsed Time: includes time between when timer is started, stopped, and reset (includes Auto Pause or manual stoppage of the timer)
Average Pace/Speed: Pace or Speed for entire duration of an activity
Moving Pace/Speed: Pace or Speed that only includes time spent moving (does not include Auto Pause)
Best Pace/Speed: Best Pace or Speed throughout the duration of an activity
Being aware of the differences between the various timing fields will assist you in utilizing them fully in evaluating your training.