Marionetas translates to "puppets". It's an evocative word that immediately brings to mind images of control and manipulation, which is central to the song's theme.
In "Dime La Verdad," Marta Sánchez uses this word to describe how people feel like they are being controlled by unseen forces, singing, "Somos unas marionetas, otros mueven los hilos" (We are puppets, others pull the strings). This metaphor powerfully conveys a sense of helplessness and the desire to uncover the truth behind who is truly in charge.