Plural of “fax”
The plural of fax is faxes.
Why
"Fax" is a 20th-century clipping of "facsimile," shortened for speed once fax machines became common office equipment in the 1970s and '80s. Despite being a modern coinage rather than an inherited word, it still follows the same ancient sibilant rule as "hoax," "box," and "fox": nouns ending in -x add -es, since a bare -s glued directly onto that final consonant cluster would be nearly impossible to pronounce cleanly.
What makes "fax" interesting historically is how fast it moved from technical jargon to ordinary vocabulary — "facsimile" had existed in English since the 1600s referring to an exact copy, but "fax" as a noun for a transmitted document, and as a verb meaning to send one, only entered common use once the machines themselves became household and office fixtures, then largely receded again as email replaced the technology, leaving "fax" as a slightly dated but still understood term.
Usage note
Because fax machines are now uncommon outside a handful of industries (legal, medical, some government offices), the plural "faxes" shows up mostly in institutional or slightly nostalgic writing rather than everyday conversation. It's still fully standard, just less frequent than it was in the 1990s.
Some younger writers unfamiliar with the technology occasionally treat "fax" as uncountable, the way one might treat "mail" in "you've got mail" — but "fax" behaves as an ordinary countable noun: one fax, several faxes, just like "form" or "letter." The technology itself is much older than the word's common use suggests — fax-like machines transmitting images over wires existed as early as the 1840s, but they remained a niche curiosity for over a century until digital fax machines became affordable enough for ordinary offices in the 1980s, which is when "fax" as an everyday noun and verb truly entered common speech.
Common real mistakes
As with "hoax," the temptation is to write "fax's" as a plural rather than a possessive, or to drop the -es entirely and write "faxs" — both nonstandard. The correct plural is always "faxes," matching the pronunciation with its extra syllable.
The wider pattern
"Fax" joins "box," "fox," "hoax," and "tax" in the small but productive family of short -x nouns that all pluralize with -es, regardless of whether the word is centuries old or, like "fax," barely fifty years old as a common noun — the spelling rule applies to new coinages exactly as it applies to inherited vocabulary. Unlike "telex" or "telegram," two other now-outdated communication technologies whose names never became productive verbs the way "fax" did, "fax" left behind a genuinely versatile pair of forms — noun and verb both fully regular — that outlived the machines themselves in everyday vocabulary even as the devices grew rare.
Examples
- She kept a folder of old faxes from her first job.
- The office received dozens of faxes before switching entirely to email.
- Two faxes arrived overnight confirming the shipment details.
- The law firm still processes faxes for certain court filings.
- He found a stack of faxes in a drawer he hadn't opened in years.
- The clinic requests medical records by fax, and receives dozens of faxes weekly.
- Several faxes were garbled by a bad phone line that day.
- The archive includes faxes documenting the negotiation in real time.
- Faxes from that era often arrived on curling thermal paper.
- The hotel's front desk still keeps a machine for incoming faxes.
- The insurance company still requires certain faxes for claims processing.
- A handful of faxes from decades ago survived in the company archive.
- Government offices exchanged faxes long after most businesses had switched to email.
- The reporter tracked down old faxes to verify the timeline of events.
- The archive preserved faxes documenting the merger negotiations step by step.
- Old faxes sometimes faded badly if stored near sunlight for years.
- The pharmacy still accepts prescription faxes from certain clinics.
- He digitized a box of faxes before recycling the paper originals.