caesium
/ˈsiːzi.əm/
"caesium" is a 7-letter English headword indexed on PlainSpell.
The verdict
“caesium” is uncommon English (frequency #75,696 among 5,599 “C” headwords), classed as a noun. The kind of spelling people second-guess.
- #75,696
- frequency rank, English
- 5,599
- “C” headwords
According to Wiktionary data (CC BY-SA, analyzed September 3, 2026) - The chemical element (symbol Cs) with an atomic number of 55. It is a soft, gold-colored, highly reactive alkali metal.
Corpus desk
Index EN-caesium · caesium · English
caesium · rank #75,696 · 0 variants · 0 confusables
- FREQ-RARE #75,696
- LEN-LONG 7 letters
- VOW-4 4 vowels
- CONFUS-0 No pairs
- VAR-0 0 variants
- BOOK-DENSE 5,599
- PHOTO-FINISH cajole
Nearest frequency peer: cajole (+1 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.
Long-tail ranks near “caesium”
Sparse band: bars invert rank so rarer forms read shorter
- bustier
bustier
24,309 corpus weight
- bux
bux
24,308 corpus weight
- BYOB
BYOB
24,307 corpus weight
- caesium
caesium
24,305 corpus weight
- cajole
cajole
24,304 corpus weight
- candela
candela
24,302 corpus weight
What this shows Long-tail view: where “caesium” sits against similarly uncommon English ranks.
| Property | Value |
|---|---|
| Headword | caesium |
| Language | English |
| Part of speech | Noun |
| IPA | /ˈsiːzi.əm/ |
| Letters | 7 |
| Frequency rank | #75,696 |
| Misspellings tracked | 0 |
| Confusable pairs | 0 |
| Source | Wiktionary (kaikki.org) |
Long-tail rank of “caesium” in English
Rare enough to double-check
caesium is uncommon English at frequency #75,696 among 5,599 “C” headwords, classed as anoun, transcribed /ˈsiːzi.əm/. Rarity is why readers land here mid-draft. Gloss: "The chemical element (symbol Cs) with an atomic number of 55. It is a soft, gold-colored, highly reactive alkali metal.".
The misspelling generator found no plausible variants for caesium, a sign its spelling follows regular English conventions. No close-neighbour confusable shows up for this headword in our dataset, which typically means the spelling is too distinctive to be mistaken for another word.
Etymologically, the entry records: From Latin caesius (“sky-blue”), in reference to the radiation spectra, + -ium. The correct English form is caesium, spelled C-A-E-S-I-U-M.
Definition
- 1The chemical element (symbol Cs) with an atomic number of 55. It is a soft, gold-colored, highly reactive alkali metal.
Etymology
From Latin caesius (“sky-blue”), in reference to the radiation spectra, + -ium.
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.
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Similar English words by spelling shape
Same letter count and similar misspelling depth for "caesium", not the corpus desk frequency band.
Same letter count
Frequency-ranked English headwords with 7 letters (nearest by frequency rank).