backfill

/ˈbækfɪl/

//ˈbækfɪl// verb

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

"backfill" is a 8-letter English headword indexed on PlainSpell.

The verdict

“backfill” is uncommon English (frequency #77,436 among 4,121 “B” headwords), classed as a verb. The kind of spelling people second-guess.

#77,436
frequency rank, English
4,121
“B” headwords

According to Wiktionary data (CC BY-SA, analyzed September 3, 2026) - To refill a hole with the material dug out of it.

Corpus desk

Index EN-backfill · backfill · English

backfill · rank #77,436 · 0 variants · 0 confusables

  • FREQ-RARE #77,436
  • LEN-LONG 8 letters
  • VOW-2 2 vowels
  • CONFUS-0 No pairs
  • VAR-0 0 variants
  • BOOK-MID 4,121
  • PHOTO-FINISH backdated

Nearest frequency peer: backdated (-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 “backfill”

Sparse band: bars invert rank so rarer forms read shorter

corpus weight

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

Source FrequencyWords open word-frequency list As of September 3, 2026
Key facts for backfill
PropertyValue
Headwordbackfill
LanguageEnglish
Part of speechVerb
IPA/ˈbækfɪl/
Letters8
Frequency rank#77,436
Misspellings tracked0
Confusable pairs0
SourceWiktionary (kaikki.org)

Long-tail rank of “backfill” in English

Every-word frequency runs from the handful of words we use constantly (left) to the long tail used once in a blue moon (right).backfillfalls in this rarity band:

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

Scale is logarithmic (each tick is 10× rarer). Rare peers in the same band: “backdated” (#77,435), “Ballston” (#77,439), “automatons” (#77,432). Among 4,121 “B” headwords, “backfill” is #77,436. Source: FrequencyWords open word-frequency list.

Rare enough to double-check

backfill is uncommon English at frequency #77,436 among 4,121 “B” headwords, classed as averb, transcribed /ˈbækfɪl/. Rarity is why readers land here mid-draft. 5 senses are on record.

No generated misspelling entries exist for backfill in our index, a straightforward case of a spelling with little room for common typos. It is not paired with a close-neighbour confusable in our dataset, which tends to mean the word is visually distinctive enough to stand on its own.

Etymologically, the entry records: From back + fill. The correct English form is backfill, spelled B-A-C-K-F-I-L-L.

Definition

  1. 1
    To refill a hole with the material dug out of it.
  2. 2
    To refill an excavation unit to restore the former ground surface and/or to preserve the unit and make it recognizable as having been excavated.
  3. 3
    To provide reserve support.
  4. 4
    To replenish or restock due to attrition or loss.
  5. 5
    To enter an online game that's already in progress, replacing a player who left early.

Recorded use

Wiktionary examples

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

  1. Clay excavated for the new river channel has been used to backfill the old watercourse, while embankment vegetation was also moved from the old channel to the new in order to preserve a habitat for the rare Four Spotted Moths that live there.
  2. We backfilled the cistern with pea gravel to discourage its use as a refuse container.

Etymology

From back + fill.

This word in other languages

atibar(Español)

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 "backfill"?
"backfill" is spelled B-A-C-K-F-I-L-L. The IPA pronunciation is /ˈbækfɪl/.
What does "backfill" mean?
As a verb, "backfill" means: To refill a hole with the material dug out of it.
How do you pronounce "backfill"?
The IPA (International Phonetic Alphabet) transcription for "backfill" is /ˈbækfɪl/. 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 "backfill"?
From back + fill. 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 "backfill", not the corpus desk frequency band.

Same letter count

Frequency-ranked English headwords with 8 letters (nearest by frequency rank).

Ballston#77,439beaucoup#77,449armorial#77,422aneurism#77,407

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

Source: FrequencyWords open word-frequency list