---
title: "Concepts"
description: "Understand what environments are, how they power evaluation, agent optimization, and training, and how the same components serve all three."
position: 2
---
Understand what environments are, how they power evaluation, agent optimization, and training, and how the same components serve all three.

---

## Concept Highlights

Each explainer below covers one foundational idea and links to deeper material.

<Cards>

<Card title="Environments" href="/about/concepts/environments">
Where the concept comes from, what components make up an environment, and how environments unify the evaluate-improve loop.
</Card>

<Card title="Evaluation" href="/about/concepts/evaluation">
How environments are used to measure model and agent performance.
</Card>

<Card title="Training" href="/about/concepts/training">
Post-training techniques and how environments are used for training.
</Card>

<Card title="Key Terminology" href="/about/concepts/key-terminology">
Essential vocabulary for agent training, RL workflows, and NeMo Gym.
</Card>

</Cards>

---
