Word.ws English Dictionary

fido

UK/ˈfaɪ.dəʊ/US/ˈfaɪ.doʊ/

fido noun: a coin that is defective, having been incorrectly minted, often prized by collectors.

Noun (1)

fido (plural fidos)

  1. A coin that is defective, having been incorrectly minted, often prized by collectors.

Noun (2) capitalized: FIDO

FIDO (plural FIDOs)

  1. (abbreviation, acronym) Acronym of flight dynamics officer.

Proper noun (1) capitalized: FIDO

FIDO

  1. (abbreviation, initialism) Initialism of Fog Investigation and Dispersal Operation.
  2. (abbreviation, initialism, computer security) Initialism of Fast IDentity Online (Alliance), an industry association launched to develop and promote authentication standards.

Proper noun (2) capitalized: Fido

Fido

  1. A stereotypical given name for a dog.
    • He [Jimmy Goodson] also passed along some water-saving tips to customers from residents Ingrid and Doug Scott. “If it’s yellow, let it mellow; if it’s brown, flush it down. Urine is a sterile liquid and the toilet is not there for the purpose of Fido getting a drink or Junior floating his rubber...2015 September 3, Dawn Gagnon, “Castine suffers water shortage: Town buying from Bucksport”, in Bangor Daily News, state edition, Bangor, Me.: Bangor Publishing Co., →ISSN, →OCLC, page B2, column 2
    • This may provide a simple explanation for the seemingly universal desire of all dogs to drink from the toilet. Since toilet water has likely been refreshed more recently than the water in Fido's bowl, it tastes better.2019, Marc Bekoff, Jessica Pierce, Unleashing Your Dog
  2. (abbreviation, clipping) Clipping of FidoNet.

Forms of fido

pluralfidos
pluralFIDOs
alternative formFDO

Origin of fido

An acronym of the words freaks, irregulars, defects, oddities, from the 1960s.

From Spanish or Italian fido from Latin fīdus (“faithful”). Popularly claimed to be directly from Latin fīdō (“to trust, rely on”) instead of the Romance intermediary, but this might be folk etymology. The stereotypical dog's name is evidently very old; a newspaper from 1760 cites, "[a] small white Greyhound with a Collar, answers to the Name of Fido."

Words that rhyme with fido

Questions about fido

What does fido mean?
Fido means a coin that is defective, having been incorrectly minted, often prized by collectors.
What part of speech is fido?
Fido can be a noun or a proper noun.
How do you pronounce fido?
Fido is pronounced /ˈfaɪ.dəʊ/ (UK).
What is the plural of fido?
The plural of fido is fidos.

Words near fido in the dictionary

  1. fidlam bens
  2. Fidler
  3. Fidlers
  4. fidlet
  5. fidlets
  6. fido
  7. Fidoer
  8. Fidoers
  9. FidoNetter
  10. FidoNetters
  11. fidos

Source and license

Adapted from Wiktionary: fido (page history and authors); FIDO (page history and authors); Fido (page history and authors). Text available under the Creative Commons Attribution-ShareAlike 4.0 license. Word.ws reformatted the entry and added links. Wiktionary data of 2026-09-02.

Last updated:

Cite this entry: “fido.” Word.ws, https://word.ws/fido. Based on Wiktionary, CC BY-SA 4.0.