jus in bello → law of war, law that regulates the conduct of warring parties

[spiros]

jus ad bellum → law of war, law that regulates the conditions for initiating war
jus in bello → law of war, law that regulates the conduct of warring parties

The law of war is the component of international law that regulates the conditions for initiating war (jus ad bellum) and the conduct of warring parties (jus in bello). Laws of war define sovereignty and nationhood, states and territories, occupation, and other critical terms of law.
Law of war - Wikipedia

als: kriegsvölkerrecht; ar: قانون الحرب; ast: lleis de la guerra; ca: dret de guerra; cs: válečné právo; de: Kriegsvölkerrecht; en: law of war; eo: milita juro; es: leyes de la guerra; fa: قانون جنگ; fi: sodan lait; fr: droit de la guerre; gl: leis da guerra; he: דיני מלחמה; hi: युद्ध विधि; hy: պատերազմի օրենքներ և սովորույթներ; it: diritto bellico; ja: 戦時国際法; ka: ომის სამართალი; ko: 전시국제법; nl: oorlogsrecht; no: krigens regler; oc: lèis de la guèrra; pt: direito de guerra; ru: законы войны; simple: laws of war; sk: vojnové právo; sl: vojno pravo; sr: међународно ратно право; sv: krigets lagar; th: กฎหมายสงคราม; tr: savaş hukuku; uk: закони та звичаї війни; vi: luật chiến tranh; yi: קריג'ס געזעצן; zh: 战争法