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 31,241 “B” headwords), classed as a verb. The kind of spelling people second-guess.

#77,436
frequency rank, English
31,241
“B” headwords

According to Wiktionary data (CC BY-SA, analyzed May 6, 2026) - To refill a hole with the material dug out of it.

Key facts for backfill
PropertyValue
Headwordbackfill
LanguageEnglish
Part of speechVerb
IPA/ˈbækfɪl/
Letters8
Frequency rank#77,436
Misspellings tracked0
Confusable pairs0
SourceWiktionary (kaikki.org)

Where “backfill” sits in English frequency

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

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

Scale is logarithmic (each tick is 10× rarer). Source: FrequencyWords open word-frequency list.

Rare enough to double-check

backfill is uncommon English at frequency #77,436 among 31,241 “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.

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.

Using “backfill”

The practical upshot for anyone who landed here from a spell-check.

  • The one correct English spelling is B-A-C-K-F-I-L-L - every other letter order is a misspelling in standard orthography.
  • Say it as /ˈbækfɪl/ (IPA); tap the speaker on the pronunciation badge to hear it where audio exists.
  • Browse more English words and confusable pairs in the same reference. English words

Other uncommon English words near this rank

Data Source

Wiktionary (via kaikki.org), licensed under CC BY-SA & GFDL. Word ordering uses an open word-frequency list; misspelling variants are generated by edit-distance from the correct headword.

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

Source: FrequencyWords open word-frequency list