What does Bro Tones mean?

Bro Tones meaning in Urban Dictionary

Short for "Brotha Tones", which can be a much required term for back up vocal parts in newer rap/hip hop songs which mostly include brief rhythmic repetition of words like "Hey", "What?", "Yo" etc. These are used to accentuate the beat and sometimes lends to syncopation, usually making the song more dance-able.