FSB

name

"fsb" is a 3-letter English headword indexed on PlainSpell.

The verdict

“FSB” sits in 20 confusable pairs (corpus #32,815) as a proper noun. The look-alike neighbours are the real trap.

#32,815
frequency rank, English
2,507
“F” headwords
20
confusable pairs

According to Wiktionary data (CC BY-SA, analyzed September 3, 2026) - The Federal Security Service of the Russian Federation.

Corpus desk

Index EN-fsb · FSB · English

FSB · rank #32,815 · 0 variants · 20 confusables

  • FREQ-MID #32,815
  • LEN-MID 3 letters
  • VOW-0 0 vowels
  • CONFUS-HIGH 20 pairs
  • VAR-0 0 variants
  • BOOK-MID 2,507
  • PHOTO-FINISH Gabriella

Nearest frequency peer: Gabriella (+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.

Frequency neighbours of confusable “FSB”

Peers at similar corpus weight, separate from look-alike pairs below

corpus weight

What this shows Bars place “FSB” against nearest ranked English headwords, not a reprint of the confusable-pair desk.

Source FrequencyWords open word-frequency list As of September 3, 2026

Visual similarity to commonly confused words

How many letter changes separate each confused pair (Levenshtein distance, normalized).

FSB vs fu
0% similar
FSB vs FW
33% similar
FSB vs fy
0% similar

Source: PlainSpell confusable corpus (Wiktionary, CC BY-SA).

Key facts for FSB
PropertyValue
HeadwordFSB
LanguageEnglish
Part of speechProper noun
Letters3
Frequency rank#32,815
Misspellings tracked0
Confusable pairs20
SourceWiktionary (kaikki.org)

Corpus rank beside confusables of “FSB”

Word frequency stretches from the small set of words we reach for constantly (left) out to the long tail barely used once in a while (right).FSBlands here:

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

Ticks step logarithmically, so each one marks a roughly tenfold drop in how often the word turns up. Same rarity band neighbours include “Gabriella” (#32,816), “frills” (#32,813), “gagged” (#32,817). Among 2,507 “F” headwords, “FSB” is #32,815. Source: FrequencyWords open word-frequency list.

Easy to mix with look-alikes

The spelling risk for FSB is neighbouring look-alikes ("fu", "FW", …), not just typos; it is aproper noun. Frequency #32,815 among 2,507 “F” headwords. Gloss: "The Federal Security Service of the Russian Federation.".

No misspelling variants are generated for FSB in our index, a straightforward case of a spelling with little room for common typos. It also participates in 20 confusable-pair relationships, "fu", "FW", "fy", and more, where similar look or sound leads writers to substitute one word for another in context.

Etymologically, the entry records: From Russian ФСБ (FSB), initialism of Федеральная Служба Безопасности (Federalʹnaja Služba Bezopasnosti, “Federal Security Service”). The correct English form is FSB, spelled F-S-B.

Definition

  1. 1
    The Federal Security Service of the Russian Federation.

Recorded use

Wiktionary examples

These source excerpts show how FSB appears in context. They illustrate usage; the definition above remains the entry’s reference meaning.

  1. Possible victims included Roman Tsepov, Putin’s bodyguard in 1990s St Petersburg, who died after drinking tea in 2004 at a local FSB office.
  2. Krasikov, a former high-ranking FSB colonel serving a life sentence in a German prison, was on the top of Moscow’s list of Russian prisoners it wanted to exchange.

Etymology

From Russian ФСБ (FSB), initialism of Федеральная Служба Безопасности (Federalʹnaja Služba Bezopasnosti, “Federal Security Service”).

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.

Frequently Asked Questions

How do you spell "FSB"?
"FSB" is spelled F-S-B.
What does "FSB" mean?
As a proper noun, "FSB" means: The Federal Security Service of the Russian Federation.
What words are commonly confused with "FSB"?
"FSB" is commonly confused with "fu", "FW", "fy". These words look or sound similar but have different meanings. PlainSpell provides detailed comparisons for each pair.
What is the origin of the word "FSB"?
From Russian ФСБ (FSB), initialism of Федеральная Служба Безопасности (Federalʹnaja Služba Bezopasnosti, “Federal Security Service”). See the full etymology section above for more details.
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.

Similar English words by spelling shape

Same letter count and similar misspelling depth for "FSB", not the corpus desk frequency band.

Same letter count

Frequency-ranked English headwords with 3 letters (nearest by frequency rank).

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

Source: FrequencyWords open word-frequency list