✦ Plain-English Tech Dictionary

The words that get you unstuck.

AI, coding, startup, and internet terms explained for beginners: one sentence, an example, and where to go next. Hit a word you don’t know in a lesson? Look it up, then get back to it.

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The words beginners get stuck on first. New to one? It is a 2-minute read.

Vibe coding Vibe coding is building software mostly by… API API is a way for two pieces of software to talk:… Deploy Deploy means to put your code live on the internet… Git Git is the tool that tracks every change to your… LLM LLM (large language model) is an AI trained on huge… RAG RAG (retrieval-augmented generation) lets an AI… MCP MCP (Model Context Protocol) is a standard way to… Database database is where an app stores its information so… Webhook webhook is an automatic message one app sends… Prompt prompt is simply what you ask an AI to do: the…

AI terms

AI agent AI agent is an AI that can take actions on its own:… Context rot Context rot is when an AI coding assistant slowly… Context window context window is how much text an AI can keep in… Conversational AI Conversational AI is AI you talk to in plain… Diffusion model diffusion model is the kind of AI that makes… Embedding embedding turns text (or images) into a list of… Fine-tuning Fine-tuning is taking a general model and training… Hallucination hallucination is when an AI states something false… Inference Inference is the moment an AI model actually runs… LLM LLM (large language model) is an AI trained on huge… MCP MCP (Model Context Protocol) is a standard way to… Model model is the trained AI itself, the thing that… Multimodal Multimodal AI can handle more than one kind of… Prompt prompt is simply what you ask an AI to do: the… RAG RAG (retrieval-augmented generation) lets an AI… Rate limit rate limit is a cap on how many requests you can… Structured outputs Structured outputs force an AI to answer in a… Temperature Temperature is a setting that controls how random… Token token is a small chunk of text an AI reads at once,… Tool calling Tool calling is when an AI decides to use an… Vector database vector database stores embeddings so an AI can…

Internet & web terms

404 error 404 error means the web page or address you asked… Browser browser is the app that turns web code into the… CDN CDN (content delivery network) stores copies of… Cookie cookie is a small note a website saves in your… DNS DNS (Domain Name System) is the internet s… Domain domain is your website s human-friendly address,… Hosting Hosting is renting space on an always-on computer… HTTP HTTP is the language browsers and servers use to… IP address IP address is the numeric address of a device on a… OAuth OAuth is the Log in with Google system: it lets one… Server server is a computer that runs all the time and… SSL / TLS SSL (now properly called TLS) is the encryption… URL URL is the full web address of a specific page,… Webhook webhook is an automatic message one app sends…

Coding terms

API API is a way for two pieces of software to talk:… API key API key is a secret password that lets your app use… Authentication Authentication (or auth ) is the system that checks… Backend backend is the part of an app you do not see: the… Boilerplate Boilerplate is routine, repetitive code that nearly… Branch branch is a parallel copy of your code where you… Build build is the step where the computer packages all… CLI CLI (command-line interface) lets you control… Commit commit is a saved checkpoint of your code: a… Console console is a running text feed where your app and… Database database is where an app stores its information so… Dependency dependency is a package your project relies on to… Deploy Deploy means to put your code live on the internet… Dev server dev server is a program on your computer that shows… Environment variable environment variable is a setting stored outside… Framework framework is a ready-made foundation for building… Frontend frontend is the part of an app you see and click:… Git Git is the tool that tracks every change to your… Localhost Localhost is a private web address that shows your… Package package is a bundle of prewritten code you can drop… Port port is the numbered door on your computer (the… Pull request pull request (PR) is a proposal to merge your… Refactor To refactor is to clean up and reorganize existing… Repository repository (or repo ) is the folder that holds all… Scaffolding Scaffolding is the empty starter skeleton of an… Schema schema is the blueprint that defines what… Stack trace stack trace is the wall of red text shown when an… Terminal terminal is the window where you type commands to… Vibe coding Vibe coding is building software mostly by…

Builder & startup terms

ARR ARR (annual recurring revenue) is the predictable… CAC CAC (customer acquisition cost) is how much you… Churn Churn is the rate at which customers cancel and… Conversion rate conversion rate is the percentage of people who… Freemium Freemium is a model where the basic product is free… LTV LTV (lifetime value) is how much money one customer… MVP MVP (minimum viable product) is the smallest… Product-market fit Product-market fit is the moment a product clearly… Production Production is the real, live version of your app… Rollback rollback is undoing a change by returning your app… SaaS SaaS (software as a service) is software you pay…