What is a Large Language Model? Check Its Definition, History, and Examples

In today’s digital world, you must have heard about AI tools like ChatGPT, Bard, or Gemini that can write essays, answer your questions, create content, or even chat with you like a human. But behind all of these is a smart tool called a Large Language Model (LLM).

I know, now,  you must be wondering what a large language model is. 

So, Large Language Models are super-smart computer brains trained on massive amounts of text, books, websites, articles, and conversations,  so it can understand and respond in human-like language. The idea of LLMs comes from the early years of AI research, but they have started making the headlines after OpenAI introduced GPT-3 in 2020, followed by GPT-4 and now even more advanced versions. 

What is a Large Language Model?

A Large Language Model (LLM) is a type of artificial intelligence (AI) designed to understand and generate human language. Think of them as incredibly advanced chatbots that have read a huge chunk of the internet.

They work using a special kind of AI design called a transformer. This design is really good at finding connections and patterns in sequences of words, which is how the LLM figures out what to say next.

History of Large Language Models

The concept of teaching computers a language is not new. Early efforts started in the 1950s when scientists dreamed of creating machines that could understand human speech. But things really took off with the introduction of transformer architecture in 2017, a breakthrough paper by Google researchers titled ‘Attention Is All You Need’.

From there, OpenAI introduced GPT-1 in 2018, which had 117 million parameters. Then came GPT-2 in 2019 with 1.5 billion parameters and GPT-3 in 2020 with 175 billion parameters. Each of their new versions is way smarter, faster, and more capable. Today’s models like GPT-4 and Gemini are pushing the boundaries even further, making LLMs a central part of AI-powered tools worldwide.

Check out: AI Term Decoded: What is Artificial Intelligence? Check Its Definition, Types, History, and Uses

Is ChatGPT a LLM?

Yes, ChatGPT is one of the most popular examples of a Large Language Model. It was created by OpenAI and is based on the GPT (Generative Pre-trained Transformer) series. ChatGPT works by predicting the next word in a conversation, but it does it so smoothly that it feels like you’re talking to a human.

What makes ChatGPT even more powerful is that it is not just answering from memory, but it also generates new responses based on the context of your question. 

List of Popular LLMs

Here are some most popular Large Language Models in 2025:

1. OpenAI GPT-4 / GPT-4.5 – Most widely used, powers ChatGPT

2. Google Gemini Ultra – Advanced AI from Google

3. Anthropic Claude 3 – Focuses on safe and aligned responses

4. Meta LLaMA 3 – Open-source and research-friendly

5. Cohere Command R – Strong in retrieval-augmented generation (RAG)

6. Mistral AI – European competitor in the LLM space