subsonic
"subsonic" is a 8-letter English headword indexed on PlainSpell.
The verdict
“subsonic” is uncommon English (frequency #52,027 among 6,566 “S” headwords), classed as an adjective. The kind of spelling people second-guess.
- #52,027
- frequency rank, English
- 6,566
- “S” headwords
According to Wiktionary data (CC BY-SA, analyzed September 2, 2026) - having a frequency too low to be audible
Corpus desk
Index EN-subsonic · subsonic · English
subsonic · rank #52,027 · 0 variants · 0 confusables
- FREQ-RARE #52,027
- LEN-LONG 8 letters
- VOW-3 3 vowels
- CONFUS-0 No pairs
- VAR-0 0 variants
- BOOK-DENSE 6,566
- PHOTO-FINISH summery
Nearest frequency peer: summery (+2 rank slots)
Read with this headword: Spelling guide for this pattern
Desk codes from Wiktionary headword shape, FrequencyWords rank tier, confusable-pair count, generated misspelling depth, letter-cohort book size, and photo-finish peer. Not a difficulty grade.
Frequency neighbourhood for “subsonic”
Lower corpus rank = more everyday usage (inverted bar length for readability)
- stringy
stringy
47,978 corpus weight
- struct
struct
47,977 corpus weight
- subsonic
subsonic
47,974 corpus weight
- summery
summery
47,972 corpus weight
- suplex
suplex
47,971 corpus weight
- survivalist
survivalist
47,970 corpus weight
What this shows Bars show where “subsonic” sits against the nearest ranked English headwords in the FrequencyWords band, not a reprint of letter-browse containment.
| Property | Value |
|---|---|
| Headword | subsonic |
| Language | English |
| Part of speech | Adjective |
| Letters | 8 |
| Frequency rank | #52,027 |
| Misspellings tracked | 0 |
| Confusable pairs | 0 |
| Source | Wiktionary (kaikki.org) |
Where “subsonic” sits in English frequency
Rare enough to double-check
subsonic is uncommon English at frequency #52,027 among 6,566 “S” headwords, classed as anadjective. Rarity is why readers land here mid-draft. 4 senses are on record.
subsonic has no tracked misspelling variants, since its letter sequence doesn't invite the usual edit-distance slips. No confusable counterpart is on file for this word, since no other headword is close enough in sound or shape to pair with it.
Etymologically, the entry records: From sub- + sonic. The correct English form is subsonic, spelled S-U-B-S-O-N-I-C.
Definition
- 1having a frequency too low to be audible
- 2very quiet, almost inaudible
- 3(aviation) less than the speed of sound (in the same medium, and at the same temperature and pressure)
- 4with a Mach number such that 0.3 < Ma < 0.8 (approximately - the exact limits vary between sources)
Recorded use
Wiktionary examplesThese source excerpts show how subsonic appears in context. They illustrate usage; the definition above remains the entry’s reference meaning.
The noise of the ship was all around her. The faint subsonic rumble of the reactor and drive. (Leviathan Wakes, James S. A. Corey)
But British Airways Flight 112 made the trek in under five hours, setting a new record for the fastest subsonic commercial flight across the Atlantic Ocean.
Etymology
From sub- + sonic.
This word in other languages
Definitions, pronunciation, and etymology for this entry are drawn from Wiktionary via the kaikki.org structured extract (CC BY-SA); frequency ordering uses the FrequencyWords open word-frequency list (2018 English corpus, MIT). See the methodology for how each field is sourced and updated.
PlainSpell is rendered directly from structured Wiktionary extracts and open word-frequency lists, no number is typed in by an editor. See our editorial standards & corrections policy, the methodology behind these numbers, or report a data error. Data current as of September 2, 2026. Primary sources: Wiktionary (via kaikki.org) and FrequencyWords.
Frequently Asked Questions
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Similar English words by spelling shape
Same letter count and similar misspelling depth for "subsonic", not the corpus desk frequency band.
Same letter count
Frequency-ranked English headwords with 8 letters (nearest by frequency rank).
Data Source
Wiktionary (via kaikki.org), licensed under CC BY-SA & GFDL. Word ordering uses an open word-frequency list; misspelling variants are generated by edit-distance from the correct headword.