ARPA
/ˈɑɹ.pə/
"arpa" is a 4-letter English headword indexed on PlainSpell.
The verdict
“ARPA” is uncommon English (frequency #66,471 among 3,931 “A” headwords), classed as a proper noun. The kind of spelling people second-guess.
- #66,471
- frequency rank, English
- 3,931
- “A” headwords
According to Wiktionary data (CC BY-SA, analyzed September 3, 2026) - Acronym of Advanced Research Projects Agency, renamed to DARPA in 1972.
Corpus desk
Index EN-arpa · ARPA · English
ARPA · rank #66,471 · 0 variants · 0 confusables
- FREQ-RARE #66,471
- LEN-MID 4 letters
- VOW-2 2 vowels
- CONFUS-0 No pairs
- VAR-0 0 variants
- BOOK-MID 3,931
- PHOTO-FINISH archaea
Nearest frequency peer: archaea (-2 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.
Long-tail ranks near “ARPA”
Sparse band: bars invert rank so rarer forms read shorter
- approbation
approbation
33,534 corpus weight
- arcadian
arcadian
33,533 corpus weight
- archaea
archaea
33,532 corpus weight
- ARPA
ARPA
33,530 corpus weight
- Atal
Atal
33,527 corpus weight
- Athlone
Athlone
33,526 corpus weight
What this shows Long-tail view: where “ARPA” sits against similarly uncommon English ranks.
| Property | Value |
|---|---|
| Headword | ARPA |
| Language | English |
| Part of speech | Proper noun |
| IPA | /ˈɑɹ.pə/ |
| Letters | 4 |
| Frequency rank | #66,471 |
| Misspellings tracked | 0 |
| Confusable pairs | 0 |
| Source | Wiktionary (kaikki.org) |
Long-tail rank of “ARPA” in English
Rare enough to double-check
ARPA is uncommon English at frequency #66,471 among 3,931 “A” headwords, classed as aproper noun, transcribed /ˈɑɹ.pə/. Rarity is why readers land here mid-draft. 4 senses are on record.
We couldn't generate a plausible misspelling set for ARPA, a sign its spelling follows regular English conventions. Our dataset records no confusable match here, which typically means the spelling is too distinctive to be mistaken for another word.
This entry carries no recorded etymology, so its spelling is easiest to reason about phoneme by phoneme, absent a documented history. The correct English form is ARPA, spelled A-R-P-A.
Definition
- 1Acronym of Advanced Research Projects Agency, renamed to DARPA in 1972.
- 2Initialism of Automatic Radar Plotting Aid.
- 3Acronym of American Rescue Plan Act.
- 4Initialism of Association for Reformed Political Action.
Recorded use
Wiktionary exampleThese source excerpts show how ARPA appears in context. They illustrate usage; the definition above remains the entry’s reference meaning.
This reverses the ARPA provision that lowered the reporting threshold to $600 with no minimum on the number of transactions.
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
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Similar English words by spelling shape
Same letter count and similar misspelling depth for "ARPA", not the corpus desk frequency band.
Same letter count
Frequency-ranked English headwords with 4 letters (nearest by frequency rank).