Two words or one? And what do "agentic engineering," "context engineering" and "spec-driven development" actually mean? A plain glossary of every AI-coding term in circulation, each with who coined it and when.
Half the internet writes "vibe coding" and half writes "vibecoding," and then there's a second argument about whether the whole thing is now called something else. Here's the plain answer to both, followed by a glossary you can skim.
Vibe coding or vibecoding?
Two words. It's not close: "vibe coding" is searched roughly fifteen times more often than "vibecoding," and when Collins Dictionary named it the 2025 Word of the Year, it used the two-word spelling. The one-word form isn't wrong — it's the name of the large r/vibecoding community, and some people prefer it — but it's the minority spelling. When you need the adjective, the common form is hyphenated: a "vibe-coded app." That's the house style on this site, and it matches how the dictionaries landed.
The glossary, dated
Most of these terms came from a small number of people in a short window. Where a term's exact first date is uncertain, this table says so rather than inventing one.
**Vibe coding**
What it means
Describing an app in plain language and letting AI write it, often without reading the code
Who coined it, and when
Andrej Karpathy, February 2025
**Vibecoding** (one word)
What it means
The same thing, minority spelling; the Reddit community's form
Who coined it, and when
Organic variant, 2025
**Vibe coder**
What it means
A person who builds this way
Who coined it, and when
Derived from the above, 2025
**Agentic engineering**
What it means
Directing AI agents to write code while you review and oversee — the "grown-up" version
Who coined it, and when
Andrej Karpathy, early February 2026
**Agentic coding**
What it means
The industry/product label for an agent that reads, edits and runs your code
Who coined it, and when
Anthropic (for Claude Code), 2025
**Context engineering**
What it means
Managing what information the AI can see so it doesn't lose the plot
Who coined it, and when
Popularised by Shopify's Tobi Lütke, then Karpathy, around mid-2025
**Spec-driven development**
What it means
Writing a clear specification first, then letting the AI build to it
Who coined it, and when
GitHub's Spec Kit (September 2025) and Amazon's Kiro
**Harness engineering**
What it means
Building the tooling and guard rails around a coding agent
Who coined it, and when
OpenAI, February 2026
**Vibe engineering**
What it means
An early proposed name for the serious version of vibe coding
Who coined it, and when
Simon Willison, October 2025
**"Pencils down"**
What it means
A slogan, not a field name: hand-writing code is now the exception
Who coined it, and when
DHH, at Rails World, September 2026
What it means
Who coined it, and when
**Vibe coding**
Describing an app in plain language and letting AI write it, often without reading the code
Andrej Karpathy, February 2025
**Vibecoding** (one word)
The same thing, minority spelling; the Reddit community's form
Organic variant, 2025
**Vibe coder**
A person who builds this way
Derived from the above, 2025
**Agentic engineering**
Directing AI agents to write code while you review and oversee — the "grown-up" version
Andrej Karpathy, early February 2026
**Agentic coding**
The industry/product label for an agent that reads, edits and runs your code
Anthropic (for Claude Code), 2025
**Context engineering**
Managing what information the AI can see so it doesn't lose the plot
Popularised by Shopify's Tobi Lütke, then Karpathy, around mid-2025
**Spec-driven development**
Writing a clear specification first, then letting the AI build to it
GitHub's Spec Kit (September 2025) and Amazon's Kiro
**Harness engineering**
Building the tooling and guard rails around a coding agent
OpenAI, February 2026
**Vibe engineering**
An early proposed name for the serious version of vibe coding
Simon Willison, October 2025
**"Pencils down"**
A slogan, not a field name: hand-writing code is now the exception
DHH, at Rails World, September 2026
Which words actually matter for you?
If you're building apps by describing them, the only word you need is vibe coding — it's what you're doing, and it's what people search. "Agentic engineering" is worth knowing as the name for the same thing done with more care (you read the code); it's what experts adopted, though search interest in it peaked in mid-2026 and has since cooled. "Context engineering" becomes useful the day your AI starts forgetting your app halfway through a session. The rest — harness engineering, vibe engineering — are mostly developer-world vocabulary you can file away until you meet them.
"Vibe coding," two words — it's about fifteen times more common and is the spelling Collins used for its 2025 Word of the Year. "Vibecoding" is the minority form, kept alive mainly by the r/vibecoding community.
Has vibe coding been renamed to agentic engineering?
No. "Agentic engineering" is the term experts adopted for the version where you review the code, but "vibe coding" is still the dominant word in search. The bar rose; the name stuck.
What's the difference between agentic coding and agentic engineering?
"Agentic coding" is a product/industry label (Anthropic uses it for Claude Code) for an agent that reads and runs your code. "Agentic engineering" is the broader skill of directing those agents with oversight. In practice people use them loosely.
Do I need to learn all these terms?
No. "Vibe coding" covers what you do; the rest are good to recognise when they come up. Chasing the vocabulary matters far less than the one habit behind it all — reading what the AI built before you ship it.
This page has no affiliate links or sponsored placements. Term origins are taken from Wikipedia, The New Stack and Simon Willison's own page; where a term's exact first date is uncertain it's given as a month or season rather than guessed, and disputed popularity stats were left out.
