The Growth Marketing Glossary: 30 Terms That Run the P&L

This glossary defines the 30 terms that decide growth budgets — each entry gives you the direct definition in the first sentence, the formula where one exists, published benchmark ranges with named sources, and an interactive calculator to run your own numbers. No dictionary padding, just the working knowledge an operator needs before a planning meeting.

Unit economics: the chain that funds everything

These six terms form a single logical chain. Contribution margin is what remains of each order after variable costs — and one division later it becomes your break-even ROAS. ROAS compares attributed revenue to ad spend at the campaign level, while MER does the same math on the whole business, immune to attribution double-counting. CAC prices a new customer, LTV values one over their lifetime, and CAC payback converts the pair into months-to-cash — the number B2B and subscription businesses live by.

Get these six straight and you can audit any growth plan in an afternoon. Our ROAS & Break-Even Calculator and CAC & LTV Calculator wrap the whole chain into working models.

Auction metrics: what the platforms charge and deliver

The vocabulary of every ad dashboard, each with cross-channel medians from the largest published datasets:

• CPM — cost per thousand impressions; Meta runs $14–15, TikTok $5–10, LinkedIn $30–35
• CPC — cost per click; the cross-industry Google Search median is $4.66
• CPL — cost per lead; Google's cross-industry median is $66.69
• CVR — conversion rate; ecommerce sites cluster at 2–3% sitewide
• CTR — click-through rate; search ads median 6.42%, social feeds near 1%
• AOV — average order value, the quietest ROAS lever available

The full channel-by-channel tables live in our Paid Media Benchmarks report, and the industry benchmark library breaks the same numbers out by vertical.

Measurement: who gets credit, and does it matter

Privacy changes broke user-level tracking, and this cluster explains what replaced it. Attribution covers the credit-assignment models and their limits. Incrementality asks the harder question — would the sale have happened anyway? Media mix modeling answers from the top down with econometrics rather than cookies. First-party data, server-side tracking and UTM parameters are the plumbing that keeps the signal flowing.

This is the daily craft of a data and analytics practice; our Attribution Doctor diagnoses the common failure patterns free.

AI search: the new distribution vocabulary

Buyers increasingly ask assistants instead of searching, and a new discipline formed around being their cited answer. AEO is optimization for answer engines broadly; GEO targets generative engines specifically. llms.txt is the proposed crawler manifest, schema markup is the structured-data layer machines read, and AI share of voice is how you measure whether any of it works.

The market context lives in our State of AI Search report, and the AI Visibility Checker grades any URL against the citability checklist in minutes.

Email infrastructure: the terms behind the inbox

Email still returns $36–42 per dollar, and three infrastructure terms decide whether yours arrives. Email deliverability is the inbox-versus-spam question itself. DMARC (with SPF and DKIM) is the authentication trio mailbox providers now mandate for bulk senders. Sender reputation is the trust score that authentication protects. Run the Email Deliverability Checker to see your domain's standing in about sixty seconds.

AI and automation: the operating layer

Three terms cover most AI conversations a marketing leader will have this year. Agentic AI distinguishes systems that plan and execute multi-step work from chat interfaces. RAG explains how AI systems answer from your documents with citations. Marketing automation maps what the LLM era changed about a fifteen-year-old category. One web-adjacent term rounds out the set: Core Web Vitals, Google's user-experience metrics with documented revenue consequences.

How to get the most from these entries

Three suggestions from watching teams use definition libraries well. First, read the unit-economics chain in order — it takes twenty minutes and permanently upgrades planning conversations. Second, when a dashboard number looks off, open the matching entry and check the calculation assumptions before debating the result; half of all metric arguments are definition arguments in disguise. Third, pressure-test your numbers against the industry benchmarks and the statistics library — a metric only means something in context.

When a definition raises a "so what do we do about it" question, the how-to guides pick up where the vocabulary ends, and the comparison series settles the either-or decisions.

The numbers worth memorizing

A handful of medians come up so often that carrying them in your head changes meetings. Google Search CPC sits at $4.66 cross-industry with a 6.42% CTR, per WordStream/LocalIQ's study — the largest published dataset. Meta CPMs blend to $14–15, with TikTok at roughly half and LinkedIn at double, per the Revealbot and Varos trackers. Ecommerce sites convert 2–3% of sessions; email returns $36–42 per dollar and drives a quarter or more of ecommerce revenue; a 0.1-second mobile speed improvement moved retail conversions 8.4% in Deloitte and Google's research. None of these is your number — the spread between average and top-quartile accounts runs 2–4x on every channel — but knowing the medians means you recognize an outlier the moment a dashboard shows one.

It's equally worth knowing which popular numbers deserve suspicion. Email open rates have been inflated by Apple's Mail Privacy Protection since 2021, so a 40% open rate mostly measures Apple's pixel-fetching. Platform-reported ROAS sums to more revenue than your bank statement across channels because each platform claims overlapping credit. And any benchmark without a named source and year has usually been photocopied between decks for half a decade. The definitions here carry sources precisely so your numbers survive contact with a skeptical CFO.

Why definitions drift, and what it costs

Every term in this glossary means slightly different things in different tools, and that slippage is expensive. GA4's "conversion rate" divides by sessions by default while your ad platform divides by clicks and your CRM divides by leads — three honest numbers, one confused meeting. CAC computed from ad spend alone runs half the fully-loaded figure that includes salaries and tools, which is how two executives can both be right about whether acquisition is affordable. The fix costs one page: write the formula, the data source, and the window for every metric your team reports, and revisit it quarterly. Teams that do this argue about strategy; teams that skip it argue about arithmetic.