Baseline activity is: the light-intensity activities of daily life, such as standing, walking slowly, and lifting lightweight objects.

Sedentary
A state of general inactivity with no exercise beyond baseline activities of daily living. 

Slightly active
A state of activity beyond that of baseline daily living but, fewer than 150 minutes of moderately intense physical activity a week.

Active
A state of activity that ranges from 150 and 300 minutes of moderately intense physical activity a week.

Highly active
A state of activity beyond 300 minutes of moderately intense physical activity a week.

Physical Activity Level (PAL) is set by Asken and is a modified version of the Institute of Medicine (IOM)'s 'Physical Activity Level'.
https://fnic.nal.usda.gov/sites/fnic.nal.usda.gov/files/uploads/107-264.pdf