pentagonal

/pɛnˈtæɡənəl/

//pɛnˈtæɡənəl// adj

"pentagonal" is a 10-letter English headword indexed on PlainSpell.

The verdict

“pentagonal” is uncommon English (frequency #86,621 among 4,417 “P” headwords), classed as an adjective. The kind of spelling people second-guess.

#86,621
frequency rank, English
4,417
“P” headwords

According to Wiktionary data (CC BY-SA, analyzed September 3, 2026) - Of, relating to, or shaped like a pentagon.

Corpus desk

Index EN-pentagonal · pentagonal · English

pentagonal · rank #86,621 · 0 variants · 0 confusables

  • FREQ-RARE #86,621
  • LEN-MEGA 10 letters
  • VOW-4 4 vowels
  • CONFUS-0 No pairs
  • VAR-0 0 variants
  • BOOK-MID 4,417
  • PHOTO-FINISH pedicel

Nearest frequency peer: pedicel (-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.

Long-tail ranks near “pentagonal”

Sparse band: bars invert rank so rarer forms read shorter

corpus weight

What this shows Long-tail view: where “pentagonal” sits against similarly uncommon English ranks.

Source FrequencyWords open word-frequency list As of September 3, 2026
Key facts for pentagonal
PropertyValue
Headwordpentagonal
LanguageEnglish
Part of speechAdjective
IPA/pɛnˈtæɡənəl/
Letters10
Frequency rank#86,621
Misspellings tracked0
Confusable pairs0
SourceWiktionary (kaikki.org)

Long-tail rank of “pentagonal” in English

This scale runs from the tiny cluster of words that carry ordinary speech (left) to the long tail of words almost nobody reaches for (right).pentagonalfalls in this rarity band:

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

The axis is logarithmic, with each marked tick roughly ten times rarer than the last. Rare peers in the same band: “pedicel” (#86,620), “peremptory” (#86,623), “Payal” (#86,617). Among 4,417 “P” headwords, “pentagonal” is #86,621. Source: FrequencyWords open word-frequency list.

Rare enough to double-check

pentagonal is uncommon English at frequency #86,621 among 4,417 “P” headwords, classed as anadjective, transcribed /pɛnˈtæɡənəl/. Rarity is why readers land here mid-draft. Gloss: "Of, relating to, or shaped like a pentagon.".

No generated misspelling entries exist for pentagonal in our index, since its letter sequence doesn't invite the usual edit-distance slips. No close-neighbour confusable shows up for this headword in our dataset, which usually means its spelling is distinct enough that readers don't reach for a similar-looking word instead.

Etymologically, the entry records: From pentagon + -al. The correct English form is pentagonal, spelled P-E-N-T-A-G-O-N-A-L.

Definition

  1. 1
    Of, relating to, or shaped like a pentagon.

Recorded use

Wiktionary examples

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

  1. If the base be a triangle, it is called a triangular prism; if a square, a square prism; if a pentagon, a pentagonal prism; and' if the base is any irregular figure, it is called an irregular prism : ...
  2. Seed micromorphology:—Seed coat is laticostate. Epidermal cells are elliptical to irregularly pentagonal. Cell walls are thickened mostly at the corners, the boundaries are raised […]

Etymology

From pentagon + -al.

This word in other languages

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 "pentagonal"?
"pentagonal" is spelled P-E-N-T-A-G-O-N-A-L. The IPA pronunciation is /pɛnˈtæɡənəl/.
What does "pentagonal" mean?
As an adjective, "pentagonal" means: Of, relating to, or shaped like a pentagon.
How do you pronounce "pentagonal"?
The IPA (International Phonetic Alphabet) transcription for "pentagonal" is /pɛnˈtæɡənəl/. 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 "pentagonal"?
From pentagon + -al. 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 "pentagonal", not the corpus desk frequency band.

Same letter count

Frequency-ranked English headwords with 10 letters (nearest by frequency rank).

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

Source: FrequencyWords open word-frequency list