bubble bubble /ˈbʌbəl/

noun

1. () A hollow globule of gas (e.g., air or carbon dioxide)  ( bubble )
   a hollow globule of gas (e.g., air or carbon dioxide)
     Children giggled and chased after the iridescent soap bubbles, filled with wonder and delight.
   Children giggled and chased after the iridescent soap bubbles, filled with wonder and delight.
   
   
2. A dome-shaped covering made of transparent glass or plastic  ( bubble )
   a dome-shaped covering made of transparent glass or plastic
    He placed a delicate bubble over the antique clock to protect it from dust.
   He placed a delicate bubble over the antique clock to protect it from dust.
   
   
3. An impracticable and illusory idea  ( bubble )
   an impracticable and illusory idea
    He didn't want to burst the newcomer's bubble
   he didn't want to burst the newcomer's bubble
   
4. A speculative scheme that depends on unstable factors that the planner cannot control  ( bubble , house of cards )
   a speculative scheme that depends on unstable factors that the planner cannot control
    His proposal was nothing but a house of cards
   his proposal was nothing but a house of cards
    A real estate bubble
   a real estate bubble
   

verb

1. () Form, produce, or emit bubbles  ( bubble )
   form, produce, or emit bubbles
    The soup was bubbling
   The soup was bubbling
   
2. Expel gas from the stomach  ( bubble , burp [Informal] , eruct , belch )
   expel gas from the stomach
    Please don't burp at the table
   Please don't burp at the table
   
3. Cause to form bubbles  ( bubble )
   cause to form bubbles
    Bubble gas through a liquid
   bubble gas through a liquid
   
4. Rise in bubbles or as if in bubbles  ( bubble )
   rise in bubbles or as if in bubbles
    Bubble to the surface
   bubble to the surface
   
5. Flow in an irregular current with a bubbling noise  ( babble , bubble , burble , guggle , gurgle , ripple )
   flow in an irregular current with a bubbling noise
    Babbling brooks
   babbling brooks