AI glossary · Beginner · Language models
Machine learning
Machine learning is a way of having a computer find rules (patterns) on its own by looking at lots of data and use them to make predictions or decisions, instead of people defining every rule by hand.
About this term
- Level
- Beginner · Core ideas for first-time readers
- Category
- Basics
- Fields
- Language models
- Added
- 2026-10-08
How it works
First, a large amount of example data is collected. The computer looks at this data, makes predictions, calculates how far off it was from the correct answers (the loss), and then adjusts its internal numbers (parameters) little by little. Repeating this process many times is called "learning" (or "training"). The result of training is called a "model," and it can produce answers from the patterns it learned even when it sees data it has never seen before.
Main types
Supervised learning, which learns from data labeled with correct answers, is used for "getting the right answer" tasks such as classifying spam email. Unsupervised learning, which groups similar data together without correct answers, is used for tasks such as dividing customers into groups. Reinforcement learning, which learns through trial and error and rewards, is used in games, robot control, and also for refining LLMs. Deep learning is one branch within machine learning.
Things to know
Machine learning depends heavily on data quality. If the data is skewed in one direction, the model will also make skewed judgments. Another common problem is "overfitting," where the model memorizes the training data and performs worse on new data. That is why it is essential to check performance separately on data that was not used for training.
Example
Spam filters in email services, recommendation features in online stores and video services, and fraud detection at credit card companies are typical uses of machine learning. For problems where people cannot write down every rule, these systems make decisions automatically using patterns learned from past data.