Paid search acronyms, explained
by Harry Watts · Last reviewed
Most of these you can safely ignore. Six of them decide whether your advertising makes money, and a handful more are worth knowing because they tell you something about the person using them.
Paid search accumulated its vocabulary over twenty-five years and never threw any of it away. Terms that described real decisions in 2012 now describe settings that no longer exist. Others get used interchangeably by people who should know better (CPA and CAC, ROAS and ROI, PPC and CPC), and the confusion is expensive, because each pair differs by exactly the amount that determines whether a campaign is profitable.
Below is every acronym you'll meet in a Google Ads account or a monthly agency report, grouped by what it's for rather than alphabetically. Each one gets a definition and what it actually means for your account, because the definition on its own has never helped anyone.
The six that matter
If you read nothing else: CAC, ROAS against your margin, CPL alongside your lead-to-customer rate, lost IS (budget), lost IS (rank), and GCLID.
Those six cover the questions that decide profitability: what a customer costs, whether the return clears your margin, whether your leads are real, whether you're constrained by money or by competitiveness, and whether you can ever connect an ad click to a closed sale. Everything else on this page is either downstream of those or a diagnostic on the way to them.
Cost and bidding
| Acronym | Stands for | What it means for your account |
|---|---|---|
| PPC | Pay per click | The advertising model, not a metric. You pay when someone clicks, not when your ad shows. |
| CPC | Cost per click | What you pay for one click. The number everyone watches and the least useful on its own: a £4 click that converts beats a 40p click that doesn't. |
| Avg. CPC | Average cost per click | What you actually paid across a period, not what you bid. Rising average CPC with flat conversions is usually the first visible symptom of a problem elsewhere. |
| Max CPC | Maximum cost per click | Your bid ceiling under manual bidding. Largely historical: smart bidding sets a bid for every individual auction and your max CPC has no role in it. |
| CPM | Cost per mille (thousand impressions) | How display and video inventory is priced. If it appears in a report about your Search campaigns, ask why. |
| CPA | Cost per acquisition, or cost per action | What the platform paid for one conversion action. The word doing the damage is "action": see below. |
| tCPA | Target CPA | A bid strategy where you name a CPA and Google bids toward it. Set the target far below your current CPA and the campaign doesn't get more efficient, it stops spending. |
| ROAS | Return on ad spend | Revenue ÷ ad spend, usually written 4:1 or 400%. Whether 4:1 is good depends entirely on your gross margin. |
| tROAS | Target ROAS | The revenue-side equivalent of tCPA, with the same failure mode in the opposite direction. |
| ECPC | Enhanced cost per click | A half-automated bidding mode from the era before smart bidding. Rarely the right answer now. |
| CPL | Cost per lead | Cost per enquiry. Meaningless without a lead-to-customer rate attached to it. |
| CPV | Cost per view | Video pricing. Not relevant to Search. |
The one that catches people out: CPA is not CAC
Cost per acquisition is what Google charges you for one conversion action: a form submission, a phone call, a checkout. Customer acquisition cost is what it costs to win one paying customer.
If your conversion action is a form fill, and one in four of those enquiries becomes a customer, your real CAC is four times your reported CPA. An account reporting a £60 CPA that looks comfortable against a £400 sale is actually running at £240 to acquire a customer, which is a different conversation.
Almost every account I look at reports CPA and calls it CAC. The gap between them is where profitability quietly lives, and it's the single most common reason a business believes its advertising works better than it does.
The same trap applies to ROAS. Break-even ROAS is 1 ÷ gross margin, so a business running 40% margins needs 2.5:1 just to stand still. A 4:1 return that everyone in the meeting is pleased with is a real but modest 1.6:1 after cost of goods. Work out what your break-even actually is before judging any campaign against a target someone else set.
Measurement and performance
| Acronym | Stands for | What it means for your account |
|---|---|---|
| CTR | Click-through rate | Clicks ÷ impressions. A relevance signal, not a goal. High CTR on unprofitable traffic is just faster spending. |
| CVR or CR | Conversion rate | Conversions ÷ clicks. Compare it within a campaign over time, not against an industry benchmark you found online. |
| IS | Impression share | The share of available auctions your ad appeared in. |
| Lost IS (budget) | Impression share lost to budget | You could have shown and didn't, because you ran out of money. |
| Lost IS (rank) | Impression share lost to rank | You could have shown and didn't, because you weren't competitive enough. |
| Abs. Top IS | Absolute top impression share | How often you held the first position above the results. Expensive to chase and rarely worth it outside brand campaigns. |
| QS | Quality Score | Google's 1–10 keyword-level rating of expected CTR, ad relevance and landing page experience. A diagnostic, not a KPI. |
| SERP | Search engine results page | The page of results itself. |
| SQR | Search query report | Now called the search terms report. What people actually typed, as opposed to what you bid on. The most valuable report in the account, and the least frequently opened. |
The one that catches people out: lost IS budget vs lost IS rank
These two columns sit next to each other and mean opposite things.
High lost IS (budget) on a campaign that converts profitably means you are leaving money on the table. The fix is more budget, and it's one of the few genuinely free wins in an account.
High lost IS (rank) means more budget will change nothing. You aren't being outspent, you're being outranked: on bid, on relevance, or on landing page quality. Adding budget to a rank-constrained campaign spends more per click for the same volume.
Adding these two columns to your campaign view takes a minute and answers a question most advertisers guess at. It's step one of any account audit.
Where to look: Campaigns → Columns → Modify columns → Competitive metrics → Search impression share, Search lost IS (budget), Search lost IS (rank).
Targeting and matching
| Acronym | Stands for | What it means for your account |
|---|---|---|
| BMM | Broad match modifier | Retired in July 2021 and folded into phrase match. Worth knowing only as a dating device: if a proposal or a blog post still recommends a BMM strategy, it was written before mid-2021 and nobody has revisited it since. |
| SKAG | Single keyword ad group | One keyword per ad group. A structure that made sense when match types were literal. Under smart bidding it fragments conversion data across too many small buckets, which slows learning. |
| STAG | Single theme ad group | The successor idea: group keywords by intent rather than isolating them. Closer to right for most accounts. |
| DSA | Dynamic Search Ads | Google generates headlines and targeting from your site content. Useful for large catalogues, dangerous without tight negative keyword coverage. |
| RLSA | Remarketing lists for search ads | Bid differently for people who've visited before. Still genuinely useful and widely unused. |
| GDN | Google Display Network | The box that comes pre-ticked when you create a Search campaign. Untick it — display inventory bought inside a Search campaign shares the budget and converts far worse. |
| PLA | Product listing ad | The older name for a Shopping ad. Still appears in reporting and third-party tools. |
| PMax | Performance Max | Google's automated cross-network campaign type. Worth running, worth watching closely. |
| DG | Demand Gen | The successor to Discovery campaigns. Upper-funnel, visual, not a Search substitute. |
The one that catches people out: PMax
Performance Max will serve against searches for your own company name and then take credit for conversions that would have happened anyway. Reported ROAS looks superb. Incremental value is close to zero, because you were going to win those customers through a cheap brand campaign or through organic results.
Published estimates put the effect at 8–15% of PMax budget consumed by branded queries and apparent ROAS inflated by 15–30%. Brand exclusions exist specifically to stop it, and the leak returns after a few months if nobody checks. This is the most common way a high-performing account is quietly overpaying.
Tracking and attribution
| Acronym | Stands for | What it means for your account |
|---|---|---|
| GA4 | Google Analytics 4 | Google's analytics platform. Answers a different question from Google Ads, which is why the two never agree. |
| GTM | Google Tag Manager | Where tracking is deployed and, more often, where duplicate conversion actions are accidentally created. |
| UTM | Urchin Tracking Module | Campaign parameters appended to a URL. Named after a company Google bought in 2005. |
| GCLID | Google click identifier | A unique string appended to every ad click. The most important twelve characters in your CRM: see below. |
| GBRAID / WBRAID | – | The iOS equivalents of GCLID, introduced when app-to-web and web-to-app journeys stopped carrying a click ID. Conversions keyed to these can take up to 72 hours to process. |
| EC | Enhanced conversions | Hashed first-party data sent back to Google to recover conversions that cookie-based tracking missed. Meaningful recovery, and a legal requirement to implement carefully. |
| OCI | Offline conversion import | Pushing CRM outcomes (qualified, closed, contract value) back into Google Ads so bidding optimises toward revenue rather than form fills. |
| CM v2 | Consent Mode v2 | Mandatory for UK and EEA traffic since March 2024. Without it, remarketing, conversion tracking and enhanced conversions degrade or stop. |
| DDA | Data-driven attribution | Google's default model, splitting credit across touchpoints rather than giving it all to the last click. |
| MTA | Multi-touch attribution | The general category DDA belongs to. |
| MMM | Marketing mix modelling | Statistical modelling of channel contribution, used where tracking can't reach. Realistic above roughly £100k a month in total marketing spend, not below. |
The one that catches people out: GCLID
Every click on your ad arrives with a GCLID attached. If your form doesn't capture it into a hidden field, and your CRM doesn't store it against the record, then the connection between that click and whatever happens next is gone permanently.
That single omission makes offline conversion import impossible. Which means Google can never learn which clicks produced revenue rather than enquiries. Which means smart bidding optimises toward whichever form fills are easiest to generate, and the easiest form fills are almost never the best customers.
For any business with a sales cycle longer than a few days, this is the highest-value tracking work available, and it takes an afternoon. It's also the thing most likely to be missing when an account looks fine on paper and disappointing in the bank.
Where to look: submit a test enquiry through your own site from a live ad click, then open the resulting record in your CRM and look for the GCLID field. If it isn't there, nothing downstream of it is possible.
Platforms and account structure
| Acronym | Stands for | What it means for your account |
|---|---|---|
| SEM | Search engine marketing | Paid search. Occasionally used to mean paid and organic together, which is why it causes arguments. |
| SEO | Search engine optimisation | Earning organic placement. Different discipline, different timeline, complementary rather than competing. |
| GMC | Google Merchant Center | Where product data lives for Shopping. Feed quality decides Shopping performance more than bidding does, and disapprovals stop products showing entirely. |
| MCC | My Client Center | Officially a "manager account" now, though nobody calls it that. How a consultant or agency gets access to your account: see below. |
| SA360 | Search Ads 360 | Google's enterprise search management platform. Relevant above roughly £250k a month. |
| MSAN | Microsoft Audience Network | Microsoft's display equivalent, and pre-ticked in Microsoft Ads much as GDN is in Google Ads. |
The one that catches people out: MCC
A manager account is how an outside specialist should access your Google Ads: your account, your billing, your data, with access granted and revocable from your side.
The alternative (campaigns built inside the agency's own account) means you never had an account of your own. Every year of conversion history, every negative keyword list, every audience you paid to build belongs to them, and it disappears the day the relationship ends. Smart bidding then starts from zero with your next provider.
This is worth checking before you sign anything, and it takes one question.
Business metrics
The ones that belong to your business rather than to the ad platform. These are the numbers advertising should be judged against.
| Acronym | Stands for | What it means for your account |
|---|---|---|
| CAC | Customer acquisition cost | Total cost to win one paying customer, including management fees. The number CPA is frequently mistaken for. |
| LTV or CLV | (Customer) lifetime value | Total gross profit from a customer across the relationship. Without it you can't tell whether a CAC is affordable. |
| LTV:CAC | – | The ratio the whole exercise is trying to move. 3:1 is the conventional healthy target for subscription businesses. |
| AOV | Average order value | Average revenue per transaction. Drives break-even ROAS alongside margin. |
| MER | Marketing efficiency ratio | Total revenue ÷ total marketing spend. A blunt cross-channel sanity check that attribution disputes can't distort. |
| COGS | Cost of goods sold | What the product costs you. The input to margin, and therefore to every ROAS target. |
| MQL / SQL | Marketing / sales qualified lead | Stages in a B2B funnel. If your Google Ads only sees MQLs, bidding optimises for volume of enquiries rather than quality of pipeline. |
Acronyms that should prompt a follow-up question
Some terms aren't wrong, but hearing them should make you ask something.
- "Our CPA is down". Down against which conversion action, and is that action a customer or a click on a phone number?
- "ROAS is 5:1". Against what margin, and does it include the management fee?
- "CTR improved". Did conversions improve, or did you just buy clicks faster?
- "We're using a BMM strategy". That setting stopped existing in July 2021.
- "Impression share is low". Lost to budget or lost to rank? Opposite problems, opposite fixes.
- "PMax is our best performer". Has brand been excluded from it?
- A report that is entirely acronyms and contains no pound signs. That was a choice, and you're allowed to ask for a different one.
That last one matters more than any definition on this page. Nobody spending their own money should have to translate a report before they can tell whether it was a good month. If yours needs translating, the problem isn't your vocabulary.
Terms worth retiring
A few appear in proposals and blog posts, and shouldn't.
Broad match modifier. Gone since July 2021.
Expanded text ads. Stopped being creatable in June 2022. Responsive search ads replaced them.
Smart Shopping and Local campaigns. Both absorbed into Performance Max.
Average position. Removed in 2019 and replaced by the impression share metrics above, because position never told you whether anyone saw the ad.
Encountering these in current advice tells you when it was written, which is more useful than the terms themselves.
If a term in your reporting isn't on this page, it's either specific to your platform or someone invented it. Both are worth querying.
More on the decisions behind these numbers in the guides.