LEGO is a toy: small plastic bricks that click together so you can build houses, cars, animals — almost anything. The name is also the company that makes them. Children play with LEGO, but it is not only a little-kid toy; some sets are made for adults. In English, people use LEGO for the brand and for the bricks themselves. Americans often say “LEGOs” for the pieces. The company would rather you say “LEGO bricks,” but you will hear both, and friends will not mind. Though actually, the firm began with wooden toys; the plastic brick came later. You write it in capital letters because it is a brand, not a common noun like “brick.”