rvsRRWhat's the difference?

Quick tell: r is a character, RR is a noun, so they fill different roles in a sentence.

Which to use

“r” is a character and “RR” is a noun - they look or sound alike but fill different roles in a sentence.

#449
“r” frequency rank
#17,232
“RR” frequency rank
17681
confusion score

Side-by-Side Comparison

Feature r RR
Definition The eighteenth letter of the English alphabet, called ar and written in the Latin script. Initialism of railroad.

Letter map: r vs RR

Shared letters muted; letters that set r and RR apart highlighted. Shared run: 1.

1 ch
r
2 ch
RR

Spelling & Dictionary Insight

Our dataset has no pronunciation recorded for both members, so the reliable separator here is grammatical: r is acharacter and RRanoun. On the page they differ by 1 extra letter(s) - “r” sits inside “RR”. Our composite confusion score for this pair is 17681, derived from the frequency rank of both members and their visual similarity.

r is recorded at frequency rank #449, classified as acharacter, pronounced /ɑː(ɹ)/. RR is at rank #17,232, tagged as anoun.

Glosses for this pair are partially populated in our dataset, but the full side-by-side definitions above should still guide you to the right choice.

With a confusion score of 17681, this pair ranks #449,836 of 530,003 scored English confusable pairs - a relatively easy-to-tell-apart pair.

Orthographic DNA of r vs RR

Shared letters: r. Private to "r": -. Private to "RR": -.

"r" · 1 letters · shape C  ·  "RR" · 2 letters · shape CC

Frequently Asked Questions

Can "r" and "RR" be used interchangeably?
No - they are not even the same part of speech. "r" is a character and "RR" a noun, so a sentence built for one is usually ungrammatical with the other.
Which is more common, "r" or "RR"?
"r" is the more common of the two: it sits at frequency rank #449 in our English list, against #17,232 for "RR". That is a wide gap, so in ordinary text the rarer spelling is the one worth double-checking.

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

Source: FrequencyWords open word-frequency list