But, but, but, my neighbor told me P mode, meant Professional.
P, S, M, and A are
shooting modes.
P = Program. The camera makes all the exposure decisions. Safe photos with absolutely zero artistic exposure considerations are made.
A = Aperture Priority. The photographer sets the aperture (DOF)/ISO the camera selects the shutter speed and cares not a whit if anything gets blurred in the photo because the shutter speed was to slow to stop the movement.
S = Shutter Priority. The photographer sets the shutter speed (motion stopping)/ISO the camera selects the aperture so DOF will be whateveer works to get the correct exposure.
M = Manual Mode. The photographer has to select each of the exposure triad settings based on the scene they are wanting to photograph.
All of the above are also influenced by the focus mode (single or continuous), focus area (single or dynamic), which of the 11 focus points, and the metering mode (spot, center-weighted, or 3D matrix) the photographer has selected.
Don't forget that the photographer also has to slect which image format the photos will be recorded to the memory card in: RAW, JPEG Fine, JPEG Normal, or JPEG Basic, and if the camera will use such features as Active D-Lighting, Long Exposure Noise Reduction, High ISO Noise Reduction, etc, etc, etc.