Brackets. Used as “parentheses within parentheses” or to indicate text that has been editorially inserted, e.g. into a quotation:
“I’ve always loved Tom Jones [the singer],” Mary said.
Not to be confused with parentheses, braces, or the things you fill out before March Madness.
To help improve the meaning of these lyrics, visit "Punctuation Marks" by The English Language and leave a comment on the lyrics box