fido

See also: Fido, FIDO, and fidò

English

Etymology

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

Noun

fido (plural fidos)

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

Translations

incorrectly minted coin

• Finnish: lyöntivirhe (fi)
• German: Fehlprägung (de) f

Further reading

• “fido”, in Merriam-Webster.com Online Dictionary, Springfield, Mass.: Merriam-Webster, 1996–present.

Anagrams

• I'd of, foid

Esperanto

Etymology

Etymology tree

Proto-Indo-European *bʰeydʰ-der.

Latin fidēsbor.

Esperanto fido

Borrowed from Latin fidēs.

Pronunciation

• IPA^(key): /ˈfido/

• Audio 1:

  (file)

• Audio 2:

  (file)

• Rhymes: -ido
• Syllabification: fi‧do

Noun

fido (uncountable, accusative fidon)

1. faith, trust

Further reading

• “fido”, in Plena Ilustrita Vortaro de Esperanto [Complete Illustrated Dictionary of Esperanto], 2020, →ISBN
• “fido”, in Reta Vortaro [Online Dictionary] (in Esperanto), 1997-2026

Italian

Pronunciation

• IPA^(key): /ˈfi.do/
• Rhymes: -ido
• Hyphenation: fì‧do

Etymology 1

Inherited from Latin fīdus (“loyal”).

Adjective

fido (feminine fida, masculine plural fidi, feminine plural fide)

1. faithful, loyal

Related terms

• fede
• fidare
• fiducia

Etymology 2

Deverbal from fidare (“trust”) +‎ -o.

Noun

fido m (plural fidi)

1. (banking) a credit concession

Etymology 3

See the etymology of the corresponding lemma form.

Verb

fido

1. first-person singular present indicative of fidare

Further reading

• fido in Collins Italian-English Dictionary
• fido in garzantilinguistica.it – Garzanti Linguistica, De Agostini Scuola Spa
• fìdo in Dizionario Italiano Olivetti, Olivetti Media Communication

Latin

Pronunciation

• (Classical Latin) IPA^(key): [ˈfiː.doː]
• (modern Italianate Ecclesiastical) IPA^(key): [ˈfiː.do]

Etymology 1

From Proto-Italic *feiðō, from Proto-Indo-European *bʰéydʰeti (“to trust”), from the root *bʰeydʰ-. The perfect participle fīsus has been connected to Ancient Greek πιστός (pistós), hinting at a derivation from Proto-Indo-European *bʰidʰtós, itself a *-tós adjective to the root *bʰeydʰ-. However, according to the linguist Ville Leppänen, Lachmann's law cannot account for the vowel-length of the Latin term, perhaps indicating that a generalized e-grade was later introduced into the pre-form.

Cognate to fidēs (“faith”) and Proto-Germanic *bīdaną.

Verb

fīdō (present infinitive fīdere, perfect active fīsus sum); third conjugation, semi-deponent

1. to trust, put confidence in

   Synonyms: cōnfīdō, crēdō

   Antonyms: diffīdō, suspicor, suspiciō

2. to rely upon

Conjugation

   Conjugation of fīdō (third conjugation, semi-deponent)

indicative		singular						plural
		first		second		third		first		second		third
active	present	fīdō		fīdis		fīdit		fīdimus		fīditis		fīdunt
	imperfect	fīdēbam		fīdēbās		fīdēbat		fīdēbāmus		fīdēbātis		fīdēbant
	future	fīdam, fīdēbō1		fīdēs, fīdēbis1		fīdet, fīdēbit1		fīdēmus, fīdēbimus1		fīdētis, fīdēbitis1		fīdent, fīdēbunt1
	perfect	fīsus + present active indicative of sum
	pluperfect	fīsus + imperfect active indicative of sum
	future perfect	fīsus + future active indicative of sum
subjunctive		singular						plural
		first		second		third		first		second		third
active	present	fīdam		fīdās		fīdat		fīdāmus		fīdātis		fīdant
	imperfect	fīderem		fīderēs		fīderet		fīderēmus		fīderētis		fīderent
	perfect	fīsus + present active subjunctive of sum
	pluperfect	fīsus + imperfect active subjunctive of sum
imperative		singular						plural
		first		second		third		first		second		third
active	present	—		fīde		—		—		fīdite		—
	future	—		fīditō		fīditō		—		fīditōte		fīduntō
non-finite forms		infinitive						participle
		active			passive			active			passive
present		fīdere			—			fīdēns			—
future		fīsūrum esse			—			fīsūrus			fīdendus, fīdundus
perfect		fīsum esse			—			fīsus			—
future perfect		fīsum fore			—			—			—
perfect potential		fīsūrum fuisse			—			—			—
verbal nouns		gerund								supine
		genitive		dative		accusative		ablative		accusative		ablative
		fīdendī		fīdendō		fīdendum		fīdendō		fīsum		fīsū

¹Chiefly pre-classical, but used poetically during the Classical period.

Derived terms

• cōnfīdō
• diffīdō

Related terms

• fidēlis

Descendants

Reflexes of an assumed variant *fīdāre:

• Italo-Romance:
  • Italian: fidare
  • Sicilian: fidari
    • → Maltese: fada
• Rhaeto-Romance:
  • Friulian: fiâ
  • Romansh: fidar, fider
• Gallo-Italic:
  • Old Lombard: fiar
• Gallo-Romance:
  • Catalan: fiar
  • French: fier
  • Occitan: fisar
    • Gascon: hidar
• Ibero-Romance:
  • Old Galician-Portuguese: fiar
    • Galician: fiar
    • Portuguese: fiar
  • Spanish: fiar

Etymology 2

Adjective

fīdō

1. dative/ablative masculine/neuter singular of fīdus (“trustworthy; faithful”)

References

• “fido”, in Charlton T. Lewis and Charles Short (1879), A Latin Dictionary, Oxford: Clarendon Press
• “fido”, in Charlton T. Lewis (1891), An Elementary Latin Dictionary, New York: Harper & Brothers
• “fido”, in Gaffiot, Félix (1934), Dictionnaire illustré latin-français, Hachette.
• Carl Meißner; Henry William Auden (1894), Latin Phrase-Book‎^[3], London: Macmillan and Co.
  • (ambiguous) historic times: historicorum fide contestata memoria
    
  • (ambiguous) historic truth: historiae, rerum fides
    
  • (ambiguous) an acknowledged historical fact: res historiae fide comprobata
    
  • (ambiguous) genuine historical truth: incorrupta rerum fides
    
  • (ambiguous) to remain loyal: in fide manere (B. G. 7. 4. 5)
    
  • (ambiguous) to undermine a person's loyalty: de fide deducere or a fide abducere aliquem
    
  • (ambiguous) having exchanged pledges, promises: fide data et accepta (Sall. Iug. 81. 1)
    
  • (ambiguous) to be bound by one's word; to be on one's honour: fide obstrictum teneri (Pis. 13. 29)
    
  • (ambiguous) a thing finds credence, is credible: aliquid fidem habet (vid. also fides under sect. VII., History)
    
  • (ambiguous) to promise an oath to..: iureiurando ac fide se obstringere, ut
    
  • (ambiguous) credit and financial position: fides et ratio pecuniarum
    
  • (ambiguous) credit is going down: fides (vid. sect. IX. 10, note fides has six...) concidit
    
  • (ambiguous) a man's credit begins to go down: fides aliquem deficere coepit
    
  • (ambiguous) credit has disappeared: fides (de foro) sublata est (Leg. Agr. 2. 3. 8)
    
  • (ambiguous) credit is low throughout Italy: fides tota Italia est angusta
    

Spanish

Etymology

From Latin fīdus.

Pronunciation

• IPA^(key): /ˈfido/ [ˈfi.ð̞o]
• Rhymes: -ido
• Syllabification: fi‧do

Adjective

fido (feminine fida, masculine plural fidos, feminine plural fidas)

1. faithful, loyal

   Synonyms: fiel, leal

Further reading

• “fido”, in Diccionario de la lengua española [Dictionary of the Spanish Language] (in Spanish), online version 23.8.1, Royal Spanish Academy [Spanish: Real Academia Española], 15 December 2025