I know this questions sounds kind of stupid but I don't get it.
My question is "What is a sensor?" The answer is obvious
"In the broadest definition, a sensor is an object whose purpose is to detect events or changes in its environment, and then provide a corresponding Output"
While making my research about sensors I realized that this definition doesn't work for Smartphones or they just don't care.
If you search for some sensors they list you something like Accelerometer, Light Sensor and so on but they don't list something like Bluetooth, Wifi, Microphon, Camera...
But they are sensors (or use sensors) as well. Why don't they list them in a sensor overview?