Toy brick is a term used to describe a type of building block, usually made of plastic, that can be used to construct models or playthings. The most popular type of toy brick is LEGO, which is a four-letter word that is often used as a synonym for the term 'toy brick'. LEGO bricks are interlocking pieces that come in a variety of shapes and sizes, allowing for the construction of a wide range of objects. LEGO has become a popular toy among children and adults alike, and is often used in educational settings to teach problem-solving and engineering skills.