It has two front chainrings and ten cogs in the rear. A 3x9 has three front chainrings and nine cogs in the rear. Although bikes used to have all types of drivetrains with 5, 6, 7, or other numbers of rear cogs, were going to start our discussion with 9-speed systems.
Neil Sedaka has a long and distinguished career as a pop singer, songwriter, and pianist. His many hits include Breaking Up Is Hard To Do (1962, 1975 slower remake), Laughter In The Rain (1975), and Bad Blood (1975).
It was Harry Nilsson's 1969 recording of Everybody's Talkin'  that put Neil's song into the pop music mainstream, a realm Neil never entered with his own recordings. Neil's biggest hit seemed to express his disdain for the public life and to telegraph his retreat from it: Everybody's talkin' at me.