What it means
کسر (kasr) means “fraction,” the mathematical concept of a part of a whole. The word is borrowed from Arabic, from the root k-s-r meaning “to break,” so a fraction is literally a broken-off piece. In Persian, it is used in mathematics classrooms and in everyday speech when talking about portions. A closely related concept is اعشار (a’shâr), meaning “decimals,” and نسبت (nesbat), meaning “ratio,” both of which overlap with kasr in certain contexts.
How to use it
- یه کسر از پیتزا برام گذاشتی؟ (ye kasr az pizzâ baram gozâshti?) “Did you leave a fraction of the pizza for me?”
- نصف یه کسره. (nesf ye kasre.) “A half is a fraction.”
- معلم گفت کسرها رو ساده کنیم. (mo’allem goft kasrhâ ro sâde konim.) “The teacher told us to simplify the fractions.”
- دو سوم یه کسر معروفه. (do-som ye kasr-e ma’rufe.) “Two thirds is a well-known fraction.”
Cultural note
Mathematics terminology in Persian is largely inherited from Arabic, reflecting centuries of Islamic scholarship in which Arabic was the dominant language of science and learning. Words like کسر entered Persian through this scholarly tradition and have remained standard in formal education. In Iran today, students encounter kasr from early primary school onward, and it appears unchanged in textbooks, exams, and everyday academic conversation.