rho

/ɹəʊ/

//ɹəʊ// noun

By · According to Wiktionary data (CC BY-SA) ·

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

The verdict

“rho” sits in 20 confusable pairs (corpus #36,739) as a noun. The look-alike neighbours are the real trap.

#36,739
frequency rank, English
3,094
“R” headwords
20
confusable pairs

According to Wiktionary data (CC BY-SA, analyzed September 3, 2026) - The seventeenth letter of the Modern Greek and Classical alphabets and the nineteenth letter of Old and Ancient.

Corpus desk

Index EN-rho · rho · English

rho · rank #36,739 · 0 variants · 20 confusables

  • FREQ-MID #36,739
  • LEN-MID 3 letters
  • VOW-1 1 vowel
  • CONFUS-HIGH 20 pairs
  • VAR-0 0 variants
  • BOOK-MID 3,094
  • PHOTO-FINISH rewatching

Nearest frequency peer: rewatching (-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 neighbourhood for “rho”

Lower corpus rank = more everyday usage (inverted bar length for readability)

corpus weight

What this shows Bars show where “rho” sits against the nearest ranked English headwords in the FrequencyWords band, not a reprint of letter-browse containment.

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).

rho vs RS
0% similar
rho vs RT
0% similar
rho vs RM
0% similar

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

Key facts for rho
PropertyValue
Headwordrho
LanguageEnglish
Part of speechNoun
IPA/ɹəʊ/
Letters3
Frequency rank#36,739
Misspellings tracked0
Confusable pairs20
SourceWiktionary (kaikki.org)

Where “rho” sits in English 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).rho lands here:

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

The axis is logarithmic, with each marked tick roughly ten times rarer than the last. Source: FrequencyWords open word-frequency list.

Easy to mix with look-alikes

The spelling risk for rho is neighbouring look-alikes ("RS", "RT", …), not just typos; it is anoun pronounced /ɹəʊ/. Frequency #36,739 among 3,094 “R” headwords. 2 recorded senses keep meaning in play.

We couldn't generate a plausible misspelling set for rho, typically a sign the spelling maps closely to how the word sounds. It also participates in 20 confusable-pair relationships, "RS", "RT", "RM", and more, since the words sound or look close enough that writers reach for the wrong one mid-sentence.

Etymologically, the entry records: From the name of the Ancient Greek letter ῥῶ (rhô). The correct English form is rho, spelled R-H-O.

Definition

  1. 1
    The seventeenth letter of the Modern Greek and Classical alphabets and the nineteenth letter of Old and Ancient.
  2. 2
    The sensitivity of the option value to the risk-free interest rate.

Recorded use

Wiktionary example

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

  1. Greek was an exercise in making the familiar strange. Its alphabet mapped onto the Roman alphabet, but only partly so, and often letters did not sound how they looked – a rho (Ρ) was not a P, and an eta (Η) was not an H.

Etymology

From the name of the Ancient Greek letter ῥῶ (rhô).

This word in other languages

ro(Español)rhô(Français)Rho(Deutsch)

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 3, 2026. Primary sources: Wiktionary (via kaikki.org) and FrequencyWords.

Frequently Asked Questions

How do you spell "rho"?
"rho" is spelled R-H-O. The IPA pronunciation is /ɹəʊ/.
What does "rho" mean?
As a noun, "rho" means: The seventeenth letter of the Modern Greek and Classical alphabets and the nineteenth letter of Old and Ancient.
What words are commonly confused with "rho"?
"rho" is commonly confused with "RS", "RT", "RM". These words look or sound similar but have different meanings. PlainSpell provides detailed comparisons for each pair.
How do you pronounce "rho"?
The IPA (International Phonetic Alphabet) transcription for "rho" is /ɹəʊ/. Click the speaker icon on the pronunciation badge above to hear it spoken aloud where audio is available.
What is the origin of the word "rho"?
From the name of the Ancient Greek letter ῥῶ (rhô). 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 "rho", not the corpus desk frequency band.

Same letter count

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

SAF#36,743Rab#36,723pon#36,713tet#36,784

What to do next

You've looked up "rho". Here's where to go from here.

  • "rho" maps to 20 confusable pairs in this vintage; the highest-scored is "RS". View pair
  • Usage frequency rank #36,739 among English headwords in this corpus. Corpus statistics
  • Browse more English words in the "R" letter cohort. R–Z browse
  • PlainSpell rotates a curated Word of the Day from the English corpus, a passive way to discover vocabulary. Word of the Day

PlainSpell is a reference corpus, not spelling advice. Verify unusual forms in context.

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