noun ·Rare ·Advanced level

Definitions

Noun

1. 1
   Initialism of non-directional beacon, a type of radiobeacon used in air navigation which transmits an omnidirectional radio signal containing no encoded information about the direction from an aircraft to the beacon. abbreviation, alt-of, initialism
2. 2
   Initialism of nuclear depth bomb. abbreviation, alt-of, initialism

Data sourced from Wiktionary, WordNet, CMU, and other open linguistic databases. Updated March 2026.