Halacha הלכה
Practical Jewish law — how a commandment becomes a concrete action today.
The word halacha comes from a root meaning «to walk»: it is not a set of dogmas but a path one walks. Its sources are the written and Oral Torah; its method is talmudic argument; its form is the codes — the Rambam, the Tur, the Shulchan Aruch with the Rema's glosses, and later the Mishnah Berurah.
Its machinery is visible from inside. Each new circumstance — electricity, medicine on Shabbat, a microphone, automation, war — calls not for invention but for analogy in the sources. Hence the genre of responsa: question and answer, tens of thousands of volumes from the geonic age to today.
A striking feature is respect for disagreement. The Talmud says «these and these are the words of the living God» and records rejected views. Yet practice must be single, so rules of decision exist — the majority, later authorities, and established custom.