Unsupervised Learning
In plain terms
Finding structure in data without labels.
Going deeper
Unsupervised learning discovers patterns, groupings, or structure in unlabeled data, like clusters or reduced dimensions. It learns without given answers.
Under the hood
Includes clustering and dimensionality reduction; evaluation is harder without ground truth.
Examples
Customer segmentation, clustering, anomaly detection, PCA, topic modeling.
Think of it like...
Like sorting a pile of mixed photos into groups without being told the categories.