AI algorithm

A fixed set of steps for getting from data to an answer. Feed the same numbers in twice and the same result comes out both times, because the procedure does not vary. What varies is what you feed it.

An algorithm is not the system, and it is not the model. It is one step: how a case gets scored, how a boundary gets drawn between two categories, how the distance between two things is measured. An AI system chains many of them together and runs them across volumes of data no person could work through, and that scale is where the results come from. The individual step is usually a piece of mathematics that has been in the textbooks for decades.