# What is an AI model?

> The trained system at the core of an AI product. Many apps are built on the same few models from a handful of companies.

Source: https://www.lumin.faith/christian-ai-glossary/model
By Andrew Kittridge · November 10, 2026

## Why it matters for Christians

Two different Christian apps may run on the same underlying model with different instructions.

## What to do

Find out which model a Christian app runs on. Two apps on the same model differ mostly in their instructions and sources, so ask about those.

## Related words

- [Large language model](https://www.lumin.faith/christian-ai-glossary/large-language-model.md): An AI model trained on vast amounts of text to predict likely next words. It powers ChatGPT, Claude, Gemini, and most Christian chat apps.
- [Fine-tuning](https://www.lumin.faith/christian-ai-glossary/fine-tuning.md): Additional training that adapts a general model to a narrower purpose or style.
- [System prompt](https://www.lumin.faith/christian-ai-glossary/system-prompt.md): Hidden instructions an app gives the model before your conversation starts. It sets tone, limits, and often theology.

Every word: [Christian AI glossary](https://www.lumin.faith/christian-ai-glossary.md)