if and only if

UK/ɪf ən(d)ˈəʊn.li ɪf/US/ɪf ən(d)ˈoʊn.li ɪf/

conjunction

Is equivalent to; implies and is implied by; is true and false in the same cases as.

“An integer is even if and only if its square is also even.”

Similar
if
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Meanings

conjunction
  1. human sciencesIs equivalent to; implies and is implied by; is true and false in the same cases as.

    An integer is even if and only if its square is also even.

    1 more example

    A rectangle is a square if and only if all four of its sides have the same length.

  2. broadlyinformalSynonym of if (with added intensity)

    I'll let you go to the concert if and only if you clean your room.

    Synonyms: if

Synonyms & antonyms

conjunctionSynonym of if (with added intensity)

Similar
if
Broader
logical connective
Also see
just in case

Translations

Arabic شَرْطَ أَنّ, فَقَط إِذَا
  • شَرْطَ أَنّ (šarṭa ʔann)implies and is implied by
  • فَقَط إِذَا (faqaṭ ʔiḏā)implies and is implied by
  • شَرِيطَةً أَنَّ (šarīṭatan ʔanna)implies and is implied by
  • فَقَط فِي حَالَة (faqaṭ fī ḥāla)implies and is implied by
Basque baldin eta soilik baldin
  • baldin eta soilik baldinimplies and is implied by
Catalan si i només si
  • si i només siimplies and is implied by
Chinese Mandarin 當且僅當 /当且仅当, 若且唯若
  • 當且僅當 /当且仅当 (dāngqiějǐndāng)implies and is implied by
  • 若且唯若 (ruòqiěwéiruò)implies and is implied by
Czech právě tehdy, když
  • právě tehdy, kdyžimplies and is implied by
Danish hvis og kun hvis
  • hvis og kun hvisimplies and is implied by
Dutch dan en slechts dan als, als en slechts als
  • dan en slechts dan alsimplies and is implied by
  • als en slechts alsimplies and is implied by
Esperanto se kaj nur se
  • se kaj nur seimplies and is implied by
Finnish jos ja vain jos
  • jos ja vain josimplies and is implied by
French si et seulement si
  • si et seulement siimplies and is implied by
German genau dann, wenn, dann und nur dann, wenn
  • genau dann, wennimplies and is implied by
  • dann und nur dann, wennimplies and is implied by
Greek αν και μόνο αν
  • αν και μόνο αν (an kai móno an)implies and is implied by
Hebrew אם ורק אם
  • אם ורק אם (im ve-rak im)implies and is implied by
Hungarian akkor és csakis akkor, ha
  • akkor és csakis akkor, haimplies and is implied by
Icelandic ef og aðeins ef, þá og því aðeins að
  • ef og aðeins efimplies and is implied by
  • þá og því aðeins aðimplies and is implied by
Irish is gá agus is leor
  • is gá agus is leorimplies and is implied by
Italian se e solo se
  • se e solo seimplies and is implied by
Lithuanian tada ir tik tada
  • tada ir tik tadaimplies and is implied by
Persian اگر و فقط اگر
  • اگر و فقط اگر (agar va faqat agar)implies and is implied by
Polish wtedy i tylko wtedy
  • wtedy i tylko wtedyimplies and is implied by
Portuguese se e somente se
  • se e somente seimplies and is implied by
Romanian dacă și numai dacă
  • dacă și numai dacăimplies and is implied by
Russian тогда́ и то́лько тогда́
  • тогда́ и то́лько тогда́implies and is implied by
Spanish si y sólo si
  • si y sólo siimplies and is implied by
Swedish om och endast om
  • om och endast omimplies and is implied by
Thai ก็ต่อเมื่อ
  • ก็ต่อเมื่อimplies and is implied by
Turkish ancak ve ancak
  • ancak ve ancakimplies and is implied by
Vietnamese khi và chỉ khi, nếu và chỉ nếu
  • khi và chỉ khiimplies and is implied by
  • nếu và chỉ nếuimplies and is implied by
Cite this entry
APA

if and only if. (n.d.). In WatkinsX Dictionary. Retrieved November 5, 2026, from https://dictionary.watkinsx.com/word/if%20and%20only%20if

MLA

“if and only if.” WatkinsX Dictionary, https://dictionary.watkinsx.com/word/if%20and%20only%20if. Accessed November 5, 2026.

Chicago

WatkinsX Dictionary, s.v. “if and only if,” accessed November 5, 2026, https://dictionary.watkinsx.com/word/if%20and%20only%20if.

Source: if and only if on Wiktionary, CC BY-SA 4.0.