Word.ws English Dictionary

if and only if

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

if and only if conjunction: is equivalent to; implies and is implied by; is true and false in the same cases as.

Conjunction

if and only if

  1. Is equivalent to; implies and is implied by; is true and false in the same cases as.
    • A rectangle is a square if and only if all four of its sides have the same length.
    • An integer is even if and only if its square is also even.
  2. (broadly, informal) Synonym of if (with added intensity)
    • I'll let you go to the concert if and only if you clean your room.
    Synonyms:
    if

if and only if meaning in Arabic, Persian, Thai and Vietnamese

if and only if in Arabic

implies and is implied by
شَرْطَ أَنّ šarṭa ʔann, فَقَط إِذَا faqaṭ ʔiḏā, شَرِيطَةً أَنَّ šarīṭatan ʔanna, فَقَط فِي حَالَة faqaṭ fī ḥāla

if and only if in Persian

implies and is implied by
اگر و فقط اگر agar va faqat agar

if and only if in Thai

implies and is implied by
ก็ต่อเมื่อ

if and only if in Vietnamese

implies and is implied by
khi và chỉ khi, nếu và chỉ nếu

Synonyms of if and only if

Questions about if and only if

What does if and only if mean?
If and only if means is equivalent to; implies and is implied by; is true and false in the same cases as.
What is if and only if in Arabic?
If and only if in Arabic is شَرْطَ أَنّ (šarṭa ʔann), فَقَط إِذَا (faqaṭ ʔiḏā), شَرِيطَةً أَنَّ (šarīṭatan ʔanna). See If and only if meaning in Arabic.
What part of speech is if and only if?
If and only if is a conjunction.
How do you pronounce if and only if?
If and only if is pronounced /ɪf ən(d)ˈəʊn.li ɪf/ (UK).

Words near if and only if in the dictionary

  1. if
  2. if a day
  3. if all else fails
  4. if all you have is a hammer, everything looks like a nail
  5. if all you've got is a hammer, everything looks like a nail
  6. if and only if
  7. if and when
  8. if anything
  9. if applicable
  10. if at all
  11. if at first you don't succeed

Source and license

Adapted from Wiktionary: if and only if (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:

Pronunciation audio from Wikimedia Commons, each file under its own free license: LL-Q1860 (eng)-Vealhurl-if and only if.wav, LL-Q1860 (eng)-Flame, not lame-if and only if.wav.

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