A long time ago in a galaxy far away, we had a little something called “AM Radio”. On AM Radio, they played something called “singles”. These singles were sometimes just that — individual songs recorded by artists. Sometimes these singles came from a flat piece of grooved vinyl called an “album”.
This being the the olden days (think approximately the time that the wonders of electricity were fully explored), sometimes you’d hear a single on the radio and you’d go to the store and buy it. The single generally had two songs, on on the A side and one on the B side. Some people took the whole power of the purchasing dollar thing further and bought entire albums.