What do a red green and white light indicate when seen together at night?

When seen together at night, a red, green, and white light typically indicate a vessel's navigation lights. The red light is on the port (left) side, the green light is on the starboard (right) side, and the white light is usually a masthead light or an all-round light at the back. This combination helps identify the direction a boat is facing and its movement, which is crucial for safe navigation on the water.