если

From есть (jestʹ) + ли (li). Appeared in the 16th-17th centuries in Western Russian, likely as a result of Polish jeśli influence[1].

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• IPA^(key): [ˈjes⁽ʲ⁾lʲɪ]

е́сли • (jésli)

1. if, in case

   Synonyms: е́жели (jéželi), ко́ли (kóli), коль (kolʹ), когда́ (kogdá)

   Я бы пошёл в кино́, е́сли бы у меня́ бы́ло вре́мя.

   Ja by pošól v kinó, jésli by u menjá býlo vrémja.

   I would have gone to the cinema if I had had time.

   а е́сли ― a jésli ― if ever

   е́сли и ― jésli i ― even if

   е́сли то́лько ― jésli tólʹko ― only if

In Russian, the conjunction е́сли (jésli) can only be used to express a condition or hypothetical situation, while the conjunction ли (li) is used to express the meaning of whether. This is different from English, where if can be used for both.

• е́сли бы (jésli by)