PPC & paid ads glossary

Every term below appears in a real agency report or platform dashboard. These are the definitions we use with clients, including why each metric matters and where it commonly misleads. Written from accounts we manage rather than copied from platform help pages.

Money and efficiency

The metrics that decide whether a campaign is worth running. Every one of them should be traceable back to your margin.

CPC — Cost per click: What you pay each time someone clicks the ad.; Set by auction, not by you. A high CPC is only a problem relative to your conversion rate: a £4 click that converts at 10% is cheaper per customer than a £1 click that converts at 1%.
CPA — Cost per acquisition: Ad spend divided by conversions.; Only useful once you define which conversion counts. We always separate cost per raw lead from cost per qualified lead, because the gap between them is where most wasted spend hides.
Allowable CPA: The most you can pay for a customer and still profit.; Derived from customer value, gross margin and the share of margin you will reinvest. This is the number that should drive bidding targets — not a competitor benchmark or an industry average.
ROAS — Return on ad spend: Revenue generated per unit of ad spend.; A 4x ROAS on a 20% margin product loses money; a 2x ROAS on a 70% margin service is excellent. Always convert ROAS into gross profit before celebrating it.
LTV — Lifetime value: Total gross profit from a customer over the relationship.; Businesses with repeat purchases can afford to lose money on the first order. If you have reliable repeat data, bid to first-year value rather than first-order value.
Blended CAC: Total marketing cost divided by total new customers.; The only figure that cannot be gamed by attribution. We report it alongside platform numbers so channel reporting can never drift away from the bank account.

Google Ads

Terms that appear in Google Ads reporting and what they imply for how an account is run.

Search campaign: Text ads shown against keyword searches.; The highest-intent inventory Google sells. Best suited to demand that already exists, and the safest starting point for local and emergency services.
Performance Max: One goal-driven campaign spanning every Google surface.; Trades placement control for reach. Needs roughly 30+ monthly conversions, valued conversions and a brand exclusion list before it can be judged fairly.
Quality Score: Google's 1–10 estimate of ad and landing page relevance.; A diagnostic, not a target. Low scores usually point to a mismatch between keyword, ad copy and landing page headline — fix the mismatch, not the score.
Impression share: The share of available auctions your ad appeared in.; Useful for judging headroom. Lost impression share to budget means demand you could buy; lost to rank means a relevance or bid problem.
Negative keywords: Terms you refuse to appear for.; The single highest-return maintenance task in a broad-match account. Reviewed weekly for the first three months in every account we run.
Local Services Ads: Google Guaranteed pay-per-lead placements above search results.; Priced per lead rather than per click, with a dispute process for irrelevant leads. Requires licence and insurance verification, and rewards review velocity heavily.

Meta Ads

Creative-led metrics. On Meta, the creative is the targeting, and these numbers say whether it is working.

Hook rate: Share of impressions that watch the first three seconds.; The earliest reliable signal of whether a creative concept will perform. Below roughly 20% we kill the concept before it accumulates spend.
Frequency: Average number of times each person saw the ad.; Rising frequency with falling results is creative fatigue, not audience exhaustion. The fix is new concepts, not a new audience.
Advantage+ / broad targeting: Letting Meta find the audience from the creative and pixel data.; Now outperforms narrow interest stacking in most accounts, provided conversion data is clean and there is enough creative variety to test against.
CAPI — Conversions API: Server-side conversion reporting to Meta.; Recovers events lost to browser restrictions. Requires a shared event ID with the browser pixel so events are deduplicated rather than double-counted.
Creative fatigue: Predictable decay in performance as an audience tires of an ad.; Plan for it: three or more new concepts per month is the maintenance dose for most small accounts, with winners iterated rather than replaced.

Tracking and measurement

If these are wrong, everything above is decoration. This is the part of an account we audit first.

Primary vs secondary conversion: What bidding chases versus what you merely observe.; Only real business outcomes belong as primary. Newsletter signups and PDF downloads as primary conversions teach the algorithm to buy browsers.
Enhanced conversions: Hashed first-party data sent with the conversion.; Improves match rates and recovers modelled conversions. Requires consent and a hashing implementation you can explain to your data protection lead.
Offline conversion import: Sending CRM outcomes back to the ad platform.; Lets you bid to qualified leads and won deals instead of raw form fills. Usually the highest-impact change available in a lead-generation account.
Consent Mode v2: Tag behaviour that adapts to a visitor's consent choices.; Configured properly, tags load denied and update on consent, preserving modelled conversions. Blocking tags outright removes the signal entirely.
Attribution window: How long after a click a conversion still counts.; Must match your real consideration period. A 30-day window on a 90-day sales cycle systematically understates return and pushes budget to the wrong campaigns.
Incrementality: The conversions that would not have happened anyway.; The only honest measure of a channel. Tested with holdouts, geo splits or brand pause tests — not with platform-reported ROAS.

Want these applied to your account?

Our written audits use exactly this vocabulary, with your own numbers in place of the examples. Read the insights library for the longer explanations, or get in touch to have someone look at your campaigns.