castrum

noun

The verdict

“castrum” is uncommon French (frequency #54,460 among 257,141 “C” headwords), classed as a noun. The kind of spelling people second-guess.

#54,460
frequency rank, French
257,141
“C” headwords

According to Wiktionary data (CC BY-SA, analyzed May 6, 2026) - Forteresse, place forte, château-fort.

Key facts for castrum
PropertyValue
Headwordcastrum
LanguageFrench
Part of speechNoun
Letters7
Frequency rank#54,460
Misspellings tracked0
Confusable pairs0
SourceWiktionary (kaikki.org)

Where “castrum” sits in French frequency

Every-word frequency runs from the handful of words we use constantly (left) to the long tail used once in a blue moon (right). castrum lands here:

#1#100#1K#10K#100K
← used constantlyrarely used →

Scale is logarithmic (each tick is 10× rarer). Source: FrequencyWords open word-frequency list.

Rare enough to double-check

castrum is uncommon French at frequency #54,460 among 257,141 “C” headwords, classed as anoun. Rarity is why readers land here mid-draft. 3 senses are on record.

The misspelling generator found no plausible variants for castrum, since its letter pattern doesn't lend itself to common typo substitutions. This headword has no recorded confusable partner, which usually means its spelling is distinct enough that readers don't reach for a similar-looking word instead.

This headword's origin isn't recorded in our source data, leaving phoneme-to-grapheme mapping as the best guide to its spelling rather than a borrowing history. The correct French form is castrum, spelled C-A-S-T-R-U-M.

Definition

  1. 1
    Forteresse, place forte, château-fort.
  2. 2
    Camp, campement. D’où étape (camp sur une route militaire).
  3. 3
    Vie dans les camps, service militaire.

Synonyms

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 French corpus, MIT). See the methodology for how each field is sourced and updated.

Frequently Asked Questions

How do you spell "castrum"?
"castrum" is spelled C-A-S-T-R-U-M.
What does "castrum" mean?
As a noun, "castrum" means: Forteresse, place forte, château-fort.
What language does "castrum" come from?
"castrum" is a French word. PlainSpell covers definitions, pronunciations, and spelling data across English, Spanish, Portuguese, French, and German.
Is PlainSpell free to use?
Yes, PlainSpell is a completely free word reference. You can look up definitions, pronunciations, confusable pairs, homophones, and spelling corrections across 5 languages without any sign-up or subscription.

Using “castrum”

The practical upshot for anyone who landed here from a spell-check.

  • The one correct French spelling is C-A-S-T-R-U-M - every other letter order is a misspelling in standard orthography.
  • Browse more French words and confusable pairs in the same reference. French words

Other uncommon French words near this 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.

Source: Wiktionary (via kaikki.org) Structured Wiktionary extract

Source: FrequencyWords open word-frequency list