ultralow frequency

noun

: a radio frequency in the lower range of the radio spectrum from about 300 Hz to 3 kHz

Communicating with subs thousands of miles away, under thousands of feet of ocean, requires ultralow frequencies …

—Noah Shachtman, Wired, August 2009

—abbreviation ULF see Radio Frequencies Table

Word History

First Known Use

1994, in the meaning defined above

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