Final answer:
A resident lying on his stomach is in the prone position, which is face-down orientation, distinct from the supine, lateral, or Fowler's positions.
Step-by-step explanation:
When a resident is lying on his stomach, the correct term to describe this position is prone. To break it down, the supine position is when a person is lying on their back facing upwards, while the prone position is when the person is face-down.
The lateral position refers to lying on either side of the body, and Fowler's position is a semi-sitting position with a specific angle of inclination to aid in breathing or to reduce tension and pressure on certain areas of the body. None of the other positions described match the face-down orientation that is characterized by the prone position.