if and only if

== English == === Pronunciation === (UK) IPA(key): /ɪf ən(d) ˈəʊn.li ɪf/ (US) IPA(key): /ɪf ən(d) ˈoʊn.li ɪf/ === Conjunction === if and only if (logic, mathematics) Is equivalent to; implies and is implied by; is true and false in the same cases as. (by extension, informal) Synonym of if (with added intensity) ==== Hypernyms ==== logical connective ==== Related terms ==== if if and when iff only if when and only when ==== Translations ==== ==== See also ==== ↔, ⇔