From Proto-Italic *apwerjō, from Proto-Indo-European *h₂epó (off, from) (whence ab) + *h₂wer- (to cover, shut) +‎ *-ye-.[1] Cognate with Sanskrit अपिवृणोति (apivṛṇoti, to close, cover), Oscan veru (door, pl.), Ancient Greek ἀείρω (aeírō, to lift, raise), Lithuanian atvérti (to open), Proto-Slavic *ot(ъ)verti (to open), and Old Armenian գեր (ger, above, hyper-). Related to operiō (to cover).





aperiō (present infinitive aperīre, perfect active aperuī, supine apertum); fourth conjugation

  1. (literal) to uncover, make or lay bare, reveal, clear
    Synonym: adaperiō
    Antonyms: vēlō, dissimulō, occultō, indūcō, operiō, obnūbō, occulō, condō, recondō, verrō, obruō, adoperiō, nūbō, tegō, abdō, abscondō, cooperiō, premō, opprimō, mergō
    • 8 CE, Ovid, Fasti 1.681:
      cum serimus, caelum ventīs aperīte serēnīs
      When we are sowing, you (pl.) clear* the sky with fair winds.
      *(In this quotation, the imperative plural aperīte is invoking the goddesses Terra and Ceres.)
  2. (figurative) to make visible, discover, show, reveal, lay open
    • 405 CE, Jerome, Vulgate Proverbs.13.16:
      Astūtus omnia agit cum cōnsiliō: quī autem fatuus est aperit stultitiam.
      The prudent man doth all things with counsel: but he that is a fool, layeth open his folly.
      (Douay-Rheims trans., Challoner rev.: 1752 CE)
  3. (figurative)
    1. to unclose, open, break open
      Synonyms: adaperiō, patefaciō
      Antonyms: interclūdō, claudō, inclūdō, arceō, obserō, operiō
      1. (figurative) to open, set up, establish, begin
    2. to open an entrance to, render accessible
    3. (transferred sense, to mental objects) to disclose something unknown, to unveil, reveal, make known, unfold, prove, demonstrate; (in general) to explain, recount
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   Conjugation of aperiō (fourth conjugation)
indicative singular plural
first second third first second third
active present aperiō aperīs aperit aperīmus aperītis aperiunt
imperfect aperiēbam aperiēbās aperiēbat aperiēbāmus aperiēbātis aperiēbant
future aperiam aperiēs aperiet aperiēmus aperiētis aperient
perfect aperuī aperuistī aperuit aperuimus aperuistis aperuērunt,
pluperfect aperueram aperuerās aperuerat aperuerāmus aperuerātis aperuerant
future perfect aperuerō aperueris aperuerit aperuerimus aperueritis aperuerint
passive present aperior aperīris,
aperītur aperīmur aperīminī aperiuntur
imperfect aperiēbar aperiēbāris,
aperiēbātur aperiēbāmur aperiēbāminī aperiēbantur
future aperiar aperiēris,
aperiētur aperiēmur aperiēminī aperientur
perfect apertus + present active indicative of sum
pluperfect apertus + imperfect active indicative of sum
future perfect apertus + future active indicative of sum
subjunctive singular plural
first second third first second third
active present aperiam aperiās aperiat aperiāmus aperiātis aperiant
imperfect aperīrem aperīrēs aperīret aperīrēmus aperīrētis aperīrent
perfect aperuerim aperuerīs aperuerit aperuerīmus aperuerītis aperuerint
pluperfect aperuissem aperuissēs aperuisset aperuissēmus aperuissētis aperuissent
passive present aperiar aperiāris,
aperiātur aperiāmur aperiāminī aperiantur
imperfect aperīrer aperīrēris,
aperīrētur aperīrēmur aperīrēminī aperīrentur
perfect apertus + present active subjunctive of sum
pluperfect apertus + imperfect active subjunctive of sum
imperative singular plural
first second third first second third
active present aperī aperīte
future aperītō aperītō aperītōte aperiuntō
passive present aperīre aperīminī
future aperītor aperītor aperiuntor
non-finite forms active passive
present perfect future present perfect future
infinitives aperīre aperuisse apertūrum esse aperīrī apertum esse apertum īrī
participles aperiēns apertūrus apertus aperiendus,
verbal nouns gerund supine
genitive dative accusative ablative accusative ablative
aperiendī aperiendō aperiendum aperiendō apertum apertū

Derived terms





  1. ^ De Vaan, Michiel (2008) “aperiō, -īre”, in Etymological Dictionary of Latin and the other Italic Languages (Leiden Indo-European Etymological Dictionary Series; 7), Leiden, Boston: Brill, →ISBN, page 46

Further reading

  • aperio”, in Charlton T. Lewis and Charles Short (1879) A Latin Dictionary, Oxford: Clarendon Press
  • aperio”, in Charlton T. Lewis (1891) An Elementary Latin Dictionary, New York: Harper & Brothers
  • aperio in Gaffiot, Félix (1934) Dictionnaire illustré latin-français, Hachette.
  • Carl Meißner, Henry William Auden (1894) Latin Phrase-Book[1], London: Macmillan and Co.
    • to open a route: viam patefacere, aperire
    • to uncover one's head: caput aperire (opp. operire)
    • to freely express one's opinions: sententiam suam aperire
    • to make an obscure notion clear by means of definition: involutae rei notitiam definiendo aperire (Or. 33. 116)
    • to explain one's sentiments: sententias (verbis) explicare, aperire
    • to open a letter: epistulam solvere, aperire, resignare (of Romans also linum incīdere)
    • to open, shut the door: ostium, fores aperire, claudere