Wikipedia
Chavrusa, also spelled chavruta or havruta ( Aramaic: חַבְרוּתָא, lit. "friendship" or "companionship"), is a traditional rabbinic approach to Talmudic study in which a pair of students analyze, discuss, and debate a shared text. It is a primary learning method in yeshivas and kollels, where students often engage regular study partners of similar knowledge and ability, and is also practiced by men and boys outside the yeshiva setting, in work, home and vacation settings. The traditional phrase is to learn b'chavrusa (בְחַבְרוּתָא, "in chavrusa"; i.e., in partnership); the word has come by metonymy to refer to the study partner as an individual, though it would more logically describe the pair.
Unlike a teacher-student relationship, in which the student memorizes and repeats the material back in tests, chavrusa-style learning puts each student in the position of analyzing the text, organizing his thoughts into logical arguments, explaining his reasoning to his partner, hearing out his partner's reasoning, and questioning and sharpening each other's ideas, often arriving at entirely new insights into the meaning of the text.
While chavrusa-style learning is traditionally practiced by men and boys, it has also become popular in women's yeshivas that study Talmudic texts. In the 2000s it was extended to telephone and internet hookups in which partners study Talmud as well as other traditional Jewish texts.