1. The main or promoted single released by a musical artist, typically the song intended for radio play and commercial success
The A-side of their new single is expected to top the charts.
O lado A do novo single deles deve chegar ao topo das paradas.
2. In the context of vinyl records or CDs, the side or track that receives the most promotional attention and airplay
Back in the 1970s, musicians would carefully choose which song would be the A-side of their releases.
Nos anos 1970, os músicos escolhiam cuidadosamente qual música seria o lado A de seus lançamentos.