ChatGPT
In plain wordsOpenAI's AI chatbot, released free to the public in November 2022, which answers questions, writes and converses in everyday language. Its sudden popularity began the current AI boom.
A conversational AI service from OpenAIOpenAI, prop. n.: The American company that makes ChatGPT and the GPT models. It began in 2015 as a nonprofit research lab and is now a for-profit company overseen by a nonprofit foundation., launched as a free research preview on 30 November 2022, through which users interact with a large language modellarge language model, n.: A computer program trained on enormous amounts of text to predict the words that come next. At vast scale, that simple skill lets it chat, answer questions, translate, summarize and write code. in a chat interface. The original version used a GPT-3.5 model fine-tuned for dialogue with supervised demonstrations and reinforcement learning from human feedbackreinforcement learning from human feedback, n.: A way of training AI using people's judgments: humans compare pairs of answers, a scoring model learns their preferences, and the AI is then trained to produce answers that score well., following the InstructGPTInstructGPT, prop. n.: A 2022 OpenAI language model trained with human feedback to follow instructions; people preferred its answers to those of a model 100 times larger, and its recipe led directly to ChatGPT. recipe; later versions have run on GPT-4GPT-4, prop. n.: OpenAI's 2023 language model, a big step up from the one behind the first ChatGPT. It scored well on many professional and academic exams and could also read images., GPT-4oGPT-4o, prop. n.: An OpenAI model from 2024 that handles text, images and speech in one system, enabling fast, natural voice conversations. Many users grew attached to its personality, which made its retirement controversial., the o-series reasoning modelsreasoning model, n.: An AI model trained to work through a problem step by step in hidden 'thinking' text before it answers. Letting it think longer generally makes it better at math, coding and planning. such as OpenAI o1OpenAI o1, prop. n.: OpenAI's first reasoning model, from 2024. Before replying it writes out a long, hidden series of steps, trying ideas and checking them, which lifted its scores on hard math, science and coding problems far above earlier chatbots'., and GPT-5GPT-5, prop. n.: OpenAI's flagship AI model from August 2025, which decides by itself whether to answer quickly or think longer. It replaced earlier models in ChatGPT and was followed by frequent upgrades. and its successors, adding web search, image understanding and generation, voice, file analysis, memory and agentic tools. It reached an estimated 100 million monthly users within about two months, then the fastest adoption of any consumer application, and by February 2026 it was reported to have about 900 million weekly users. Its release set off the competitive race among technology companies, and the surge of public and policy attention to AI, that followed.
Within weeks of ChatGPT's launch, schools were rewriting their homework policies.
Origin
Grew out of OpenAI's InstructGPT work and was announced in the blog post 'Introducing ChatGPT'; the name joins 'chat' to GPT (generative pre-trained transformer). Greg Brockman reported a million users within five days. 'ChatGPT moment' soon became shorthand for a sudden leap in public awareness of a technology, as in 'a ChatGPT moment for robotics'.
Usage note
Often used generically for any AI chatbot, as brand names drift into common nouns. Paid plans, beginning with Plus in February 2023 and later including business, enterprise and higher-priced Pro tiers, followed the free service.
Related
- large language modellarge language model, n.: A computer program trained on enormous amounts of text to predict the words that come next. At vast scale, that simple skill lets it chat, answer questions, translate, summarize and write code.
- OpenAIOpenAI, prop. n.: The American company that makes ChatGPT and the GPT models. It began in 2015 as a nonprofit research lab and is now a for-profit company overseen by a nonprofit foundation.
- GPT-4GPT-4, prop. n.: OpenAI's 2023 language model, a big step up from the one behind the first ChatGPT. It scored well on many professional and academic exams and could also read images.
- InstructGPTInstructGPT, prop. n.: A 2022 OpenAI language model trained with human feedback to follow instructions; people preferred its answers to those of a model 100 times larger, and its recipe led directly to ChatGPT.
- reinforcement learning from human feedbackreinforcement learning from human feedback, n.: A way of training AI using people's judgments: humans compare pairs of answers, a scoring model learns their preferences, and the AI is then trained to produce answers that score well.
- chatbotchatbot, n.: Software you chat with in ordinary language, by typing or talking, as you would with a person. The newest ones, such as ChatGPT, can answer questions, draft writing and keep long conversations going.
- GPT-5GPT-5, prop. n.: OpenAI's flagship AI model from August 2025, which decides by itself whether to answer quickly or think longer. It replaced earlier models in ChatGPT and was followed by frequent upgrades.
Sources
- OpenAI (2022). Introducing ChatGPT. OpenAI blog, 30 November 2022.
Mentioned in
chatbotchatbot, n.: Software you chat with in ordinary language, by typing or talking, as you would with a person. The newest ones, such as ChatGPT, can answer questions, draft writing and keep long conversations going., ClaudeClaude, prop. n.: A family of AI assistants and language models made by the company Anthropic since 2023, widely used for writing, analysis and computer programming., GeminiGemini, prop. n.: Google's family of AI models and its chatbot assistant, launched in December 2023. Gemini models handle text, images, audio and video and power many Google products., generative AIgenerative AI, n.: AI that produces something new on request, such as an essay, a picture, a song or a piece of code, having absorbed from enormous numbers of existing examples what such things typically look like., GPTGPT, abbr.: Short for 'generative pre-trained transformer', the family of OpenAI models behind ChatGPT. The letters are also used loosely for any similar chatbot model., GPT-5GPT-5, prop. n.: OpenAI's flagship AI model from August 2025, which decides by itself whether to answer quickly or think longer. It replaced earlier models in ChatGPT and was followed by frequent upgrades., large language modellarge language model, n.: A computer program trained on enormous amounts of text to predict the words that come next. At vast scale, that simple skill lets it chat, answer questions, translate, summarize and write code., OpenAIOpenAI, prop. n.: The American company that makes ChatGPT and the GPT models. It began in 2015 as a nonprofit research lab and is now a for-profit company overseen by a nonprofit foundation., reinforcement learning from human feedbackreinforcement learning from human feedback, n.: A way of training AI using people's judgments: humans compare pairs of answers, a scoring model learns their preferences, and the AI is then trained to produce answers that score well., Sam AltmanSam Altman, prop. n.: An American entrepreneur who co-founded OpenAI and runs it; the company's 2022 release of ChatGPT turned him into one of the public faces of the AI era., AI assistantAI assistant, n.: An AI program, such as ChatGPT, Claude or Gemini, that helps a person through conversation: answering questions, writing, summarizing, coding and, increasingly, taking actions on their behalf., BaiduBaidu, prop. n.: China's largest search-engine company and an early investor in deep learning, which makes the Ernie chatbot and models and runs driverless taxis., chat modelchat model, n.: A language model trained to hold a back-and-forth conversation, keeping track of who said what and replying as a helpful assistant. It is the engine inside chat apps., ChatGPT momentChatGPT moment, n.: A phrase for the point when a technology suddenly becomes impressive and widely used, as ChatGPT did in late 2022; people ask when robotics, biology or other fields will get theirs., GPT-3GPT-3, prop. n.: A huge 2020 OpenAI language model that could perform new tasks simply from instructions or a few examples written into its prompt, without retraining. It made prompting a new way of programming., GPT-4GPT-4, prop. n.: OpenAI's 2023 language model, a big step up from the one behind the first ChatGPT. It scored well on many professional and academic exams and could also read images., GPT-4oGPT-4o, prop. n.: An OpenAI model from 2024 that handles text, images and speech in one system, enabling fast, natural voice conversations. Many users grew attached to its personality, which made its retirement controversial., GrokGrok, prop. n.: The AI chatbot and model family of Elon Musk's company xAI, launched in 2023 and built into the social network X. It is known for its irreverent style and for repeated controversies over its outputs., Ilya SutskeverIlya Sutskever, prop. n.: A Russian-born Israeli-Canadian computer scientist who co-built the AlexNet image recognizer, helped found OpenAI and lead its research until 2024, and now heads the startup Safe Superintelligence Inc., InstructGPTInstructGPT, prop. n.: A 2022 OpenAI language model trained with human feedback to follow instructions; people preferred its answers to those of a model 100 times larger, and its recipe led directly to ChatGPT., John SchulmanJohn Schulman, prop. n.: An American AI researcher who invented widely used reinforcement-learning algorithms such as PPO, co-founded OpenAI, and led the post-training work behind ChatGPT., LangChainLangChain, prop. n.: A popular free software toolkit, and the company behind it, for building applications that connect AI language models to documents, databases, tools and multi-step workflows., machine understandingmachine understanding, n.: Whether, and in what sense, an AI system grasps what words, situations or problems mean — rather than just producing answers that look as though it does., Mira MuratiMira Murati, prop. n.: An Albanian-born American engineer who, as OpenAI's chief technology officer, oversaw the launch of ChatGPT, and who founded the AI company Thinking Machines Lab in 2025.