ID3 is a popular algorithm used in machine learning for creating decision trees. It helps classify data by splitting it into branches based on feature values, making it easier to make predictions. The algorithm selects the best attribute to split the data at each node, aiming to maximize information gain, which measures how well a feature separates the data into different classes. The name ID3 stands for "Iterative Dichotomiser 3," and it was developed by Ross Quinlan in the 1980s. ID3 is widely used in various applications, including data mining and artificial intelligence, due to its simplicity and effectiveness in handling categorical data.