The word 人声鼎沸 is formed by combining the literal elements 人声 (human voices) and 鼎沸 (cauldron boiling), where 人 means "people", 声 means "sound", 鼎 means "ancient cauldron", and 沸 means "boiling". It directly constructs a metaphor comparing the loud, chaotic sound of many people talking to the vigorous bubbling noise of a boiling cauldron, thus conveying the meaning of a noisy and bustling atmosphere.