1. A test of public opinion 
2. A balloon sent up to test air currents

Derived forms: trial balloons

Type of: balloon, dummy run [Brit], test, trial, trial run, tryout

Encyclopedia: Trial balloon

• identity crisis
• identity element
• identity matrix
• identity operator
• identity theft
• identity verification
• ideogram
• ideograph
• ideographic
• ideographically
• ideography
• ideologic
• ideological
• ideological barrier
• ideologically
• ideologist
• ideologue
• ideology
• ides
• idesia
• Idesia polycarpa
• IDF
• idioblast
• idiocy
• idiograph