boo

Boo is the sound we pretend ghosts make as well as a sound we make when we really don’t like something.

Boo is also an affectionate term for one’s significant other, similar to bae.

Boo is familiar to many as Boo!, that noise ghosts and monsters are said to make when they pop out and scare somebody, probably ultimately based on the attention-getting sound of the syllable boo. Latin and Greek also have verbs, as it happens, that also use the boo sound for “shouting” or “crying.”

The phantom boo appears as early as 1738 in a book by Gilbert Crokatt called Scotch Presbyterian Eloquence Display’d, which defined it as “a word that’s used in the north of Scotland to frighten crying children.” The 1808 Etymological Dictionary of the Scottish Language suggests boo is connected to the mythical Bu-Man, a word apparently related to bogeyman.

What about when people or an audience say boo to condemn a performance, person, or action? While jeering and heckling can be found in accounts of ancient Greek plays, the term boo for the action doesn’t appear until at least 1825 in a theater book called The London Stage.

In the 20th century, boo has been used as slang for a range of things, including marijuana, snot, idiot, and excellent, and is part of other exclamations such as boo-hoo (mocking crying) and booyah (a celebratory cheer). A boo-boo is a children’s term for a minor injury or a mistake.

Boo is also slang for a romantic partner (e.g., my boo, or “sweetheart.”) Maybe from a form of baby or connected to the French beau(x), the pet boo, used much like bae, emerges in 1990s hip-hop slang and spread from there.

A notable early use of the affectionate boo comes in the lyrics of hip-hop group A Tribe Called Quest’s 1990 song “Go Ahead in the Rain”: “Lifeless ventures ain’t new, boo.” The same year, rapper Grand Daddy I.U. spit the line: “Yo, boo, I like you, but I like others too.”

The term began popping up on Urban Dictionary in the early 2000s. Its use was further popularized in 2004, when Usher and Alicia Keys released the single “My Boo,” which contains the chorus “You will always be my boo.”

Fun fact: One of the oldest instances of boo in the written record comes in the expression to say boo to a goose, found in the 17th century. That’s not to startle the bird, but “to speak up,” a figure of speech that became to say boo, or “to stick up for yourself.”

Boo! is used as a sound we imagine ghosts make, usually in a friendly manner, or when people try to jump out and scare someone: Boo! This boo appears in all sorts of Halloween-themed events (Boo! at the Zoo) and puns (It’s a boo-tiful day!)

To boo someone, or booing, is a way to jeer them, particularly if you’re an audience member.

Boo is also a term of affection for a significant other, often as a term of address, e.g., I love you, boo. Boo can also be extended to other loved ones, such as children.

Me and my boo vibing in animal crossing <3 pic.twitter.com/Y8NcYFQTVA

— Reekid (@ReeKidwastaken) May 13, 2020

More examples of boo:

“Ghost Just Dropped By To Say ‘Boo’”
—The Onion, September 2007

“The Toronto crowd booing Lebron whenever he touches the ball is ridiculous.”
—@StephenAmell, May 2018

This content is not meant to be a formal definition of this term. Rather, it is an informal summary that seeks to provide supplemental information and context important to know or keep in mind about the term’s history, meaning, and usage.