speed of light
"speed-of-light" is a 12-letter English headword indexed on PlainSpell.
The verdict
“speed of light” is uncommon English (outside the top frequency list), classed as a noun. The kind of spelling people second-guess.
- Unranked
- below top-frequency English
- 14
- letters
According to Wiktionary data (CC BY-SA, analyzed September 3, 2026) - The speed of electromagnetic radiation, which in a perfect vacuum is equivalent to 299,792,458 metres per second.
Corpus desk
Index EN-speed-of-light · speed of light · English
speed of light · unranked · 0 variants · 0 confusables
- FREQ-UNRANKED Unranked
- LEN-MEGA 14 letters
- VOW-4 4 vowels
- CONFUS-0 No pairs
- VAR-0 0 variants
- BOOK-THIN "S" thin
- PHOTO-UNK Peer pending
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.
| Property | Value |
|---|---|
| Headword | speed of light |
| Language | English |
| Part of speech | Noun |
| Letters | 14 |
| Misspellings tracked | 0 |
| Confusable pairs | 0 |
| Source | Wiktionary (kaikki.org) |
Long-tail rank of “speed of light” in English
Rare enough to double-check
speed of light is uncommon English outside the top frequency list, classed as anoun. Rarity is why readers land here mid-draft. 3 senses are on record.
Zero misspellings are on record for speed of light in our index, suggesting the orthography follows predictable English patterns. This headword has no recorded confusable partner, since nothing in our dataset looks or sounds close enough to cause mix-ups.
No explicit etymology string is stored for this entry, so its spelling is best read as a straightforward mapping from sound to letter. The correct English form is speed of light, spelled S-P-E-E-D- -O-F- -L-I-G-H-T.
Definition
- 1The speed of electromagnetic radiation, which in a perfect vacuum is equivalent to 299,792,458 metres per second.
- 2A very rapid speed.
- 3A rate of travel of a signal equal to one cell per generation, the fastest possible speed in the Moore and von Neumann neighborhoods.
Recorded use
Wiktionary examplesThese source excerpts show how speed of light appears in context. They illustrate usage; the definition above remains the entry’s reference meaning.
Early physicists developed insightful methods for measuring the speed of light.
As the subjective speed of light is raised within the field, objects outside will appear to red-shift, eventually becoming visible only to radio telescope antennae.
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). See the methodology for how each field is sourced and updated.