This is a plain-language glossary of the terms you meet when buying advertising across television, outdoor, digital screens and press. Each entry is one short definition, written so it makes sense without reading the one before it. Twenty-four terms, from CPM to OpenRTB.
Terms are grouped by what they are about rather than alphabetically, because that is how they are actually used.
Connected TV is a television set connected to the internet, either through its own software or a device plugged into it. Ads are served to the screen digitally, one household at a time, instead of being broadcast to everyone watching a channel at the same moment.
Linear TV is traditional broadcast television, where a channel transmits a fixed schedule and everyone watching at that moment sees the same ad break. Advertising is bought as time slots within those breaks rather than as impressions delivered to individual households.
Out-of-home advertising is any advertising placed in public physical space: roadside billboards, street furniture such as bus shelters and kiosks, urban panels, and transit. It reaches people while they move through a place rather than while they use a device.
Digital out-of-home is the subset of outdoor advertising served on digital screens: streets, shopping centres, gyms, stations and venues. Because the screen is digital, a slot can rotate between advertisers, be changed remotely, and be priced per thousand impressions rather than per period.
In-stream video ads play inside video content on a publisher site or a streaming service. Pre-roll runs before the content starts, mid-roll during a natural pause. Out-stream video, by contrast, appears inside editorial text with no publisher video involved.
An impression is one delivery of an ad to a screen. It counts the ad being served, not that anyone looked at it or remembered it. Impressions are the unit most digital and DOOH inventory is measured and priced in.
Reach is the number of distinct people who saw a campaign at least once, as opposed to the total number of impressions. Two hundred impressions shown to the same fifty people are two hundred impressions but a reach of fifty.
Frequency is the average number of times each person reached saw the ad. A frequency cap is a limit set on it, so budget is not spent showing the same ad repeatedly to the same person instead of finding new ones. On Publicit the cap is set in days: 1, 3, 5, 7 or 10.
A gross rating point expresses campaign weight as a percentage of a target audience, calculated as reach percentage multiplied by frequency. Fifty per cent of the target seeing an ad three times is 150 GRPs. It is the traditional planning currency of television and outdoor.
CPM is the price of one thousand ad impressions. It is the standard unit for digital and DOOH inventory: total media cost equals the CPM rate multiplied by impressions delivered, divided by one thousand. A space at a 4 euro CPM delivering 200,000 impressions costs 800 euros in media.
Programmatic advertising is buying and selling ad inventory through software rather than through a person negotiating each placement. Most programmatic buying happens in automated auctions, though it also covers direct deals executed through the same pipes.
Real-time bidding is an auction held for a single ad impression while a page or a stream is loading, typically resolved in tens of milliseconds. Buyers submit bids, the highest wins, and the ad is served. Publicit Ad-Exchange is engineered for sub-5ms p99 bid response latency.
An ad exchange is the marketplace where programmatic buying and selling meet: it receives inventory from the sell side, requests bids from the buy side, runs the auction and returns the winning ad. It is infrastructure rather than a place an advertiser logs into.
A supply-side platform is the software a publisher uses to offer its inventory for programmatic sale, set the rules for who may buy it and at what minimum price, and connect to exchanges. It represents the seller's interests in the auction.
A demand-side platform is the software an advertiser or agency uses to buy programmatic inventory across many sources at once, applying targeting, budget and bidding rules. It represents the buyer's interests in the auction and usually charges a fee on spend.
OpenRTB is the IAB Tech Lab protocol that standardises the messages exchanged during real-time bidding, so any compliant buyer and seller can trade without a custom integration. Publicit normalises its omnichannel inventory into OpenRTB-compatible formats.
A floor price is the minimum a publisher will accept for a space or an impression. Bids below it are rejected. It lets a media owner protect the perceived value of its inventory rather than selling at whatever the auction produces.
Fill rate is the share of a publisher's available ad opportunities that were actually sold and filled with an ad. A low fill rate means inventory went unsold, which is usually a signal about pricing, demand or how the space is described.
A media plan is the set of specific spaces a campaign will run on, with their dates, formats and prices. On a self-service marketplace the advertiser assembles it directly by adding spaces, rather than receiving it as a proposal from an agency.
A self-service platform lets an advertiser create an account, build a campaign, choose placements, upload creative and pay without a sales call or an account manager. The trade-off is that nobody plans the campaign for you and you supply the creative yourself.
Escrow is money held by a third party until agreed conditions are met. On Publicit an advertiser's payment is held rather than passed straight to the publisher, and is released once the placement has run and the publisher has submitted evidence of delivery that was accepted.
The Model Context Protocol is an open standard that lets an AI assistant connect to external tools and data through a defined interface, instead of a custom integration per assistant. Publicit runs a native MCP server, so campaigns can be managed in plain language from a compatible assistant.
sellers.json is an IAB Tech Lab transparency file published by a company that sells advertising, declaring the sellers it represents so a buyer can verify who is in the supply chain. Publicit publishes one at publicit.com/sellers.json.
The Transparency and Consent Framework is IAB Europe's standard for collecting and passing user consent for advertising data under the GDPR, with a public register of participating vendors. Publicit Global S.L. is a registered TCF v2.2 vendor.
Definitions as of September 2026. Where a term describes something specific to Publicit, that detail is stated as such.