side boob

or side·boob

[ sahyd-boob ]
/ ˈsaɪdˌbub /
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Slang: Sometimes Vulgar. the outer curve of a woman's breast when revealed by clothing cut low under the arms: She's flashing too much side boob.
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Origin of side boob

Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2022


What does side boob mean?

Side boob refers to when a sizable portion of a woman’s breast is exposed from the side, as often happens when someone is wearing a tank-top without a bra or a revealing evening dress.

Content warning: the following content includes references to sexual content.

Where did the term side boob come from?

Side boob is the cleavage for the sides of the breast. It’s not to be confused with the inner boob or underboob.

One early instance of the term was posted online in January 1997 by a woman who wrote in a boxing Usenet group that her husband had noticed a “side boob shot of the ring girl.” As far as books go, side boob first appeared in a 2002 novel by Christina Bartolomeo called, aptly enough, The Side of Angels.

By the mid-2000s, the term side boob was a go-to among celebrity gossipers, who crowned Lindsay Lohan the queen of the side boob. Paparazzi had a knack for capturing Lohan’s side boob whenever it made an appearance, so much so that some people said accidentally exposing some side boob was “pulling a Lohan.” She couldn’t shake the association: In 2013, a Jezebel article featured a picture of Lohan in discussion of the side boob. 

Side boob made its Urban Dictionary debut in 2005, always an important milestone in any contemporary slang term. In 2011, Family Guy made the side boob a central plot element when starring character Peter Griffin hosted a “Side Boob Hour,” culminating in him showing off his own man-boob side boob.

Side boob enjoyed a spate of attention in the popular press in the mid-2010s, as the Jezebel article shows. Search interest in the term peaked in 2017, perhaps a banner month for the side boob when gossipers salivated over glimpses of side boob from the likes of Selena Gomez and Kendall Jenner.

Search interest has since dropped off. Maybe because people are looking up side butt instead. That’s a thing.

Who uses the term side boob?

Side boob is mostly used in the singular, a kind of mass noun, though the plural side boobs is occasionally seen as well.

Side boob comes up in a few contexts. The first is as an object of gossip or attraction. Think tabloids and lusty online lookers who all enjoy side boob for different reasons.

Another is cultivating the side boob as a point of style or fashion mags discussing it for avant-garde new looks.

The side boob can be embarrassing, though, when they happen accidentally, such as when a breast slips out of a bikini or if a dress is too loose.

While usually used of women, never think men are immune to the side boob.

More examples of side boob:

“Jesinta Franklin’s empowering self-love message: ‘I am not defined by my side boob’”
MSN (headline), January 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.

How to use side boob in a sentence