subsonic.
having a frequency too low to be audible
Meaning & usage
having a frequency too low to be audible
very quiet, almost inaudible
(aviation) less than the speed of sound (in the same medium, and at the same temperature and pressure)
with a Mach number such that 0.3 < Ma < 0.8 (approximately - the exact limits vary between sources)
Where this word comes from
Etymology tree Proto-Indo-European *upó Proto-Italic *supo Latin sub Latin sub-der. English sub- Proto-Indo-European *swenh₂- Proto-Indo-European *swónh₂os Latin sonus Proto-Indo-European *-ikos Proto-Italic *-ikos Latin -icuslbor. Old French -iquebor. Middle English -ik English -ic English sonic English subsonic From sub- + sonic.
an aircraft whose maximum speed is less than the speed of sound
Where this word comes from
Etymology tree Proto-Indo-European *upó Proto-Italic *supo Latin sub Latin sub-der. English sub- Proto-Indo-European *swenh₂- Proto-Indo-European *swónh₂os Latin sonus Proto-Indo-European *-ikos Proto-Italic *-ikos Latin -icuslbor. Old French -iquebor. Middle English -ik English -ic English sonic English subsonic From sub- + sonic.
Try it on your idea.
subsonic has 8 characters. Say it out loud, try it alongside a description of your project, and see whether its meaning fits what you want to create.
These are naming prompts. Meanings and pronunciation can vary; existing brand and domain uses have not been checked.
Explore the name generatorA word with a source.
Definitions, grammatical labels, IPA, etymology and examples: Wiktionary contributors, extracted by Kaikki / Wiktextract. Adapted under CC BY-SA 4.0. Selected fields and authored examples are shown; third-party quotations and audio are omitted. See contributor history.
Last enriched 2026-09-10. Definitions are in English. Romanizations are shown when supplied by the source; syllable estimates are omitted for unsupported scripts.