What it means
خلاء (khalâ) comes from the Arabic root kh-l-w, meaning emptiness or to be empty, and it entered Persian as the word for a vacuum or absolute void. In physics, it refers to a space containing no matter. In everyday Persian it is also used for the void of outer space, though it emphasizes the emptiness aspect rather than space as a place: فضا (fazâ) means space or the cosmos more broadly, while خلاء specifically underscores the absence of matter. You will see خلاء in scientific texts about vacuum pumps, space physics, and thermodynamics. In philosophical Persian it can also carry the sense of an existential void.
How to use it
- در خلاء صدا منتقل نمیشه. (dar khalâ sedâ montaghel nemi-she.) “Sound does not travel in a vacuum.”
- ماهواره در خلاء فضا شناور است. (mâhvâre dar khalâ-ye fazâ shanâvar ast.) “The satellite floats in the void of space.”
- پمپ خلاء اتاق رو از هوا تخلیه کرد. (pomp-e khalâ otâq ro az havâ takhlie kard.) “The vacuum pump evacuated the room of air.”
- یه خلاء قانونی وجود داره. (ye khalâ-ye qânuni vojud dâre.) “A legal vacuum exists.”
Cultural note
The Arabic philosophical tradition that entered Persian intellectual life through medieval scholars used خلاء extensively in debates about whether a true vacuum could exist in nature, a question debated by Islamic peripatetic philosophers influenced by Aristotle. The word therefore has roots in Persian scientific discourse going back to figures like Ibn Sina (Avicenna), who wrote in Arabic but whose works were read and taught in Persian intellectual circles for centuries. Today خلاء appears in both physics textbooks and in figurative language, such as خلاء مدیریتی (khalâ-ye modiriyati), a management vacuum.