Final answer:
Doo-wop is a genre of music known for its specific vocal sounds and harmonies produced by backup singers, typically characterized by catchy nonsensical phrases like "doo-wop".
Step-by-step explanation:
The general label doo-wop referred to the specific sounds and vocal harmonies that the backup singers used in the genre of music commonly known as doo-wop. This style of music was characterized by its vocal group harmony, with a lead singer and a chorus of backup singers who provided the nonsensical syllables that often made up the catchy background support, like "doo-wop" or "shoo-bop." These backup vocalists played a crucial role in the music, underpinning the melody with their repetitive, engaging phrases and complex harmonies.