Involving several different countries, groups, or sides at once. A multilateral trade deal is one signed by many countries together, not just two. The word sits in a small family that students meet together: unilateral (one side acts alone), bilateral (two sides), multilateral (many sides). It is a formal word — you meet it in news reports, government statements, and business writing, almost never in ordinary conversation. Nobody says "let's make this dinner multilateral." It also carries a quiet flavour of approval in political writing: when a leader says a problem 'needs a multilateral solution', they usually mean no single country should decide alone, and that everyone should sit at the same table. The opposite word, unilateral, often carries the opposite flavour — acting without asking anyone. So the word is not only about counting sides; it often hints at fairness and shared decision-making. There is a second, drier use in technical and geometry-flavoured writing, where it simply means 'having many sides', but a learner will almost always meet the political and economic sense first. Notice too that it describes things, not people: talks, agreements, aid, institutions, negotiations. A person cannot be multilateral; the meeting they attend can be.