automatic direction finder

noun

: a navigational tool that continuously displays the bearing of a designated reference radio beacon

But unlike some other relics, the ADF (automatic direction-finder) keeps rearing its ugly head like an uninvited relative who shows up at the family picnic. Instrument pilots who try to fly without a good foundation in ADF needlework can quickly run smack into an indigestible hash of headings and bearings.

—Thomas H. Block, Plane & Pilot, January 1994

—abbreviation ADF

Word History

First Known Use

1938, in the meaning defined above

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