IslavsISRTell them apart

Quick tell: Isla is a name, ISR is a noun, so they fill different roles in a sentence.

Which to use

“Isla” is a name and “ISR” is a noun - they look or sound alike but fill different roles in a sentence.

#23,318
“Isla” frequency rank
#49,434
“ISR” frequency rank
72752
confusion score

Side-by-Side Comparison

Feature Isla ISR
Definition A river in Angus and Perth and Kinross, east-central Scotland, tributary to the Tay. Initialism of interrupt service routine.

Letter map: Isla vs ISR

Shared letters muted; letters that set Isla and ISR apart highlighted. Shared run: 2. Isla runs 4 letters (VCCV) against ISR's 3 (VCC) - the length gap alone is often enough to separate them once you know to check it.

4 ch
Isla
3 ch
ISR

Grammar separator: Isla vs ISR

Our dataset has no pronunciation recorded for both members, so the reliable separator here is grammatical: Isla is aname and ISRanoun. On the page they differ by 1 letter(s) in length. Our composite confusion score for this pair is 72752, derived from the frequency rank of both members and their visual similarity.

Isla is recorded at frequency rank #23,318, classified as aname, pronounced /aɪlə/. ISR is at rank #49,434, 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 72752, this pair ranks #41,979 of 530,003 scored English confusable pairs - among the most confusable pairs.

Orthographic DNA of Isla vs ISR

Shared letters: is. Private to "Isla": al. Private to "ISR": r.

"Isla" · 4 letters · shape VCCV  ·  "ISR" · 3 letters · shape VCC

Known mistypes of this pair

  • Isla ← isal · islla · issla · sila

Frequently Asked Questions

Is swapping "Isla" for "ISR" ever safe?
No - they are not even the same part of speech. "Isla" is a name and "ISR" a noun, so a sentence built for one is usually ungrammatical with the other.
In ordinary English text, does "Isla" or "ISR" show up more?
"Isla" is the more common of the two: it sits at frequency rank #23,318 in our English list, against #49,434 for "ISR". The two are close in frequency, so neither is a safe default; check the meaning rather than guessing.

What to do next

Done with this confusable. These links stay specific to "Isla" and "ISR".

  • Full dictionary entry for "Isla" with definition, IPA, and generated misspellings. Word entry
  • Full dictionary entry for "ISR" - compare definitions side by side with the headword page. Word entry
  • This pair ranks #41,979 of 530,003 scored English confusable pairs in this corpus vintage. Corpus statistics
  • "Isla" and "ISR" also get mixed up with nearby pairs, the highest-scored neighbour is "ISR vs ith". Nearby pair
  • Recorded mistypes exist for at least one side of this pair, useful when a spell-checker or OCR lands on the wrong form. See mistypes

Confusion rank #41,979 of 530,003 scored English pairs, corpus vintage 2026-09-03, not spelling advice.

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

Source: FrequencyWords open word-frequency list