post office box

noun

"post-office-box" is a 13-letter English headword indexed on PlainSpell.

The verdict

“post office box” is uncommon English (outside the top frequency list), classed as a noun. The kind of spelling people second-guess.

Unranked
below top-frequency English
15
letters

According to Wiktionary data (CC BY-SA, analyzed September 3, 2026) - A uniquely addressable lockable box located on the premises of a post office that may be hired as collection point for mail.

Corpus desk

Index EN-post-office-box · post office box · English

post office box · unranked · 0 variants · 0 confusables

  • FREQ-UNRANKED Unranked
  • LEN-MEGA 15 letters
  • VOW-5 5 vowels
  • CONFUS-0 No pairs
  • VAR-0 0 variants
  • BOOK-THIN "P" thin
  • PHOTO-UNK Peer pending

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.

Key facts for post office box
PropertyValue
Headwordpost office box
LanguageEnglish
Part of speechNoun
Letters15
Misspellings tracked0
Confusable pairs0
SourceWiktionary (kaikki.org)

Long-tail rank of “post office box” in English

post office boxsits beyond the 100,000 most-frequent English words, in the long tail of technical, archaic, or otherwise rare vocabulary where spelling doubt tends to strike hardest.

Beyond rank #100,000. Source: FrequencyWords open word-frequency list.

Rare enough to double-check

post office box is uncommon English outside the top frequency list, classed as anoun. Rarity is why readers land here mid-draft. 2 senses are on record.

Zero misspellings are on record for post office box in our index, and the word's spelling is regular enough that our generator found nothing worth flagging. Our dataset records no confusable match here, since its spelling is unusual enough that it doesn't cluster with a lookalike.

No documented word history exists for this headword, so spelling patterns must be inferred from the word's phoneme-to-grapheme mapping rather than from a documented borrowing chain. The correct English form is post office box, spelled P-O-S-T- -O-F-F-I-C-E- -B-O-X.

Definition

  1. 1
    A uniquely addressable lockable box located on the premises of a post office that may be hired as collection point for mail.
  2. 2
    A test instrument once used by telephone engineers.

Recorded use

Wiktionary example

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

  1. “Rich people use post office boxes to shield themselves from unwanted correspondence. It’s like a garbage can for mail.”

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). See the methodology for how each field is sourced and updated.

Frequently Asked Questions

How do you spell "post office box"?
"post office box" is spelled P-O-S-T- -O-F-F-I-C-E- -B-O-X.
What does "post office box" mean?
As a noun, "post office box" means: A uniquely addressable lockable box located on the premises of a post office that may be hired as collection point for mail.
What language does "post office box" come from?
"post office box" is a English word. You can look up definitions, pronunciations, and spelling data for this and other words across English, Spanish, Portuguese, French, and German on PlainSpell.
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.

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

Source: FrequencyWords open word-frequency list