# What is Graph Neural Network? Definition & Technical Mechanics

> **Source:** [SPIDITS AI AI Glossary](https://spidits.com/ai-glossary)  
> **Category:** Neural Architectures  
> **Canonical Citation:** [https://spidits.com/ai-glossary/graph-neural-network](https://spidits.com/ai-glossary/graph-neural-network)

## Definition
A Graph Neural Network (GNN) is a class of artificial neural network designed to process data represented as graphs (consisting of nodes and edges), extracting features through message-passing neighborhoods.

## Architectural Mechanics & Deep Dive
A Graph Neural Network (GNN) is a specialized class of deep neural networks designed to process data structured as graphs (nodes and edges). GNNs capture relational dependencies and structural patterns by passing messages between neighboring nodes, widely used for molecular chemistry analysis, social network modeling, recommendation systems, and fraud detection.

## Industry Applications & Real-World Use Cases
Molecular drug discovery, social network connection maps, and recommendation graphs.

## Frequently Asked Questions

### What is message passing in a GNN?
The process where nodes aggregate feature information from their neighboring nodes and edges to update their own representation state.

### Why are GNNs needed for graph data instead of standard networks?
Standard networks assume grid structures (like images) or sequences (like text). Graph data is non-Euclidean with variable connections, requiring permutation-invariant operations.

## Related Terminology
- [neural-network](https://spidits.com/ai-glossary/neural-network)
- [deep-learning](https://spidits.com/ai-glossary/deep-learning)
- [knowledge-graph](https://spidits.com/ai-glossary/knowledge-graph)

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*From the SPIDITS AI Knowledge Base (336+ terms indexed). Explore full technical definitions: [https://spidits.com/ai-glossary](https://spidits.com/ai-glossary)*