a meteorological balloon used to observe air currents
pilot balloon in American English
a small balloon sent up to determine the direction and velocity of the wind
pilot balloon in American English
noun
a balloon for the visual observation of upper-atmosphere wind currents
Word origin
[1840–50]This word is first recorded in the period 1840–50. Other words that entered Englishat around the same time include: colloid, dope, sensationalism, set piece, striation
Examples of 'pilot balloon' in a sentence
pilot balloon
The forecasts became more detailed as geographical knowledge improved and more data was collected from pilot balloons and aircraft.