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Concept dictionary

Loss Function

Loss is the value a model tries to reduce during training because it measures how wrong the current output is.

Review state
Reviewed in POC
Freshness
Current
Version
2

Also called

  • Loss Function
  • Loss
  • Objective Function

Remember it this wayThe loss function turns error into the signal training follows.

In plain language

A loss function converts the difference between a model’s output and the desired result into a value the training process can minimize. Different losses encode different kinds of error.

Why it matters

The loss function tells the optimizer what to reward and penalize. A poorly chosen loss can improve the training number while producing behavior that misses the real goal.

Example

A classifier uses cross-entropy loss so confident wrong predictions receive a larger penalty than correct predictions.

Common misconception

Loss is not the same as a business outcome or an evaluation metric. It is an optimization signal, and a lower training loss does not guarantee better real-world performance.

Related terms

Sources

Learn more

  • Compare [[training|Training]], [[ml-target|ML Target]], [[evaluation-metric|Evaluation Metric]], and [[parameters|Parameters]] to place Loss Function in the surrounding system.
  • Follow the cited source material above for the method, standard, or research context behind this draft.

Reviewed in POC · last human review 2026-09-03 · content version 2 · visual version 1

Source and POC details

Source: learning-library/glossary/terms/loss-function/term.md

Source hash: sha256:0e4a11157f5b5b7fac9fda09e0b062cbad54a31217fca17429710b3962f9ada2

Media: POC-reviewed evidence; RS AI Learning Lab, Owned production asset.

Release: glossary-team-poc-0.5.5-2026-09-02 · not production approved