Meaning

noun a cry or noise made to express displeasure or contempt

verb show displeasure, as after a performance or speech

originFrom earlier (15c.) boh, coined to create a loud and startling sound. Compare Middle English bus! (“bang!”, interjection), Latin boō (“cry aloud, roar, shout”, verb), Ancient Greek βοάω (boáō, “shout”, verb).

Etymology from Wiktionary, CC BY-SA 3.0