Wiktionary
n. (context comics English) A speech bubble that conveys thought, especially one that emanates from the thinker by a path of small circles.
Usage examples of "thought balloon".
When the bland and blustery fellow arrived,Gyro was happy to see that his accompanying thought balloon -- despite theongoing life-or-death crisis -- reflected the man's typical vacuity, consistingmostly of an empty white canvas with some children's primer figures -- Dick,Jane, and Spot -- romping about.
There, in her thought balloon, was exactly that image, of Juele painting an image of a gorgeous, motherly woman in ermine and pearls.
But Julie was pushing past Nicholas Bonner and through the dancers, shaking her head at him as urgently as if his temptation were flashing above him in a bubbly comic-strip thought balloon.
The image of an ice-cold beer vanished like a pricked thought balloon as the mine supervisor moved to deal with the latest recalcitrant.