Bubble

1. n. A person deceived by an empty project; a gull.
2. n. A thin film of liquid inflated with air or gas; as, a soap bubble; bubbles on the surface of a river.
3. n. A small quantity of air or gas within a liquid body; as, bubbles rising in champagne or aerated waters.
4. n. A globule of air, or globular vacuum, in a transparent solid; as, bubbles in window glass, or in a lens.
5. n. A small, hollow, floating bead or globe, formerly used for testing the strength of spirits.
6. n. The globule of air in the spirit tube of a level.
7. n. Anything that wants firmness or solidity; that which is more specious than real; a false show; a cheat or fraud; a delusive scheme; an empty project; a dishonest speculation; as, the South Sea bubble.

The word meanings were obtained from OPTED(The Online Plain Text English Dictionary), which is based on “The Project Gutenberg Etext of Webster’s Unabridged Dictionary” which is in turn based on the 1913 US Webster’s Unabridged Dictionary (See Project Gutenburg), as a text file.