A-side

/ˈeɪsˈaɪd/

A-side

the side of a musical record that is regarded as the main release and is more likely to be successful

Examples

1. My uncle wrote the A-side of this next song, but it didn't become a hit.

2. so I play a lot of six-side football campus league, there’s the six-a-side and eleven-a-side for that