radio balloon

noun

: a small unmanned sounding balloon carrying diminutive radio sets for transmitting meteorological recordings to ground observers or for measuring cosmic rays in the stratosphere

The Ultimate Dictionary Awaits

Expand your vocabulary and dive deeper into language with Merriam-Webster Unabridged.

1. Expanded definitions
2. Detailed etymologies
3. Advanced search tools
4. All ad-free

Discover what makes Merriam-Webster Unabridged the essential choice for true word lovers.

Start Your Free Trial Now