In basketball, the term "Bubble" refers to the precarious position of teams that are on the cusp of making it into a tournament or playoff bracket.
These "Bubble Teams" have a record that puts them right on the edge of qualification, with their fate often determined by how they and other contending teams perform in the final games of the season.
The term is most commonly used in reference to the NCAA Division I Men's and Women's Basketball Tournaments.
In the lead-up to "Selection Sunday," when the tournament fields are announced, teams are often described as being on the bubble if they are one of the last few teams that could make it into the field of 68.
To be considered a Bubble Team, a squad typically needs to have a respectable record and strength of schedule. They may have a few impressive wins on their resume, but also some questionable losses.
The selection committee takes into account a variety of factors when determining which bubble teams make the cut, including record, strength of schedule, quality wins, and performance in their conference tournament.
Some notable bubble teams in recent years include Syracuse University in 2016 and the University of California Los Angeles in 2015, both of whom snuck into the tournament field and then made surprising runs to the Final Four.
In 2011, Virginia Commonwealth University was one of the last teams selected to the tournament, but they rode that momentum all the way to the Final Four as well.
The bubble isn't exclusive to college basketball, though.
In professional leagues like the National Basketball Association, the term can be used to describe teams that are on the verge of making the playoffs.
Of note for the NBA is their 2020 COVID-19 Bubble.
The 2020 NBA bubble was an innovative solution that allowed the 2019-20 season to safely conclude during the pandemic, though it required major adjustments from teams and sparked debate about how to view the championship won in that unprecedented environment.
The season was completed without any COVID-19 outbreaks among the participants.