Violão is the Portuguese word for an acoustic guitar, a central instrument in many Brazilian and Portuguese music genres, including Fado, which Carlos Do Carmo is famous for.
In this song, the violão isn't just an instrument; it's a vessel for emotion. The lyrics mention "Das cordas do meu violão / Que só teu amor procurou / Vem uma voz" (From the strings of my guitar / That only sought your love / Comes a voice), personifying the guitar as a companion in the singer's quest for love. It's a beautiful and culturally significant word that evokes the soul of Portuguese music.