A spherically contained volume of air or other gas in a liquid, commonly a soapy liquid. • A small spherical cavity in a solid material. • Anything resembling a hollow sphere. • Anything lacking firmness or solidity; a cheat or fraud; an empty project. • A period of intense speculation in a market, causing prices to rise quickly to irrational levels as the metaphorical bubble expands, and then fall even more quickly as the bubble bursts. • The emotional or physical atmosphere in which a subject is immersed; especially, a homogeneous atmosphere in which subjects are spared exposure to culture or ideas different from their own. • An officer's station in a prison dormitory, affording views on all sides. • Someone who has been ‘bubbled’ or fooled; a dupe. • A small, hollow, floating bead or globe, formerly used for testing the strength of spirits. • The globule of air in the chamber of a spirit level. • A laugh. • A Greek. • Any of the small magnetized areas that make up bubble memory. • In a poker tournament, the point before which eliminated players receive no prize money and after which they do; the situation where all remaining players are guaranteed prize money (in this case, the players are said to have made the bubble); the situation where all remaining players will be guaranteed prize money after some small number of players are eliminated (in this case, the players are said to be on the bubble). • The cutoff point between qualifying, advancing or being invited to a tournament, or having one's competition end. • A quarantine environment containing multiple people or facilities isolated from the rest of society. • The people who are in this quarantine. • Ellipsis of travel bubble. • A bulb or lamp; the part of a lighting assembly that actually produces the light. • A specialized glass pipe having a sphere-shaped apparatus at one end.