Glossary

The vocabulary of this channel is unusually dense and unusually badly explained elsewhere. Everything here is defined as it is used in this guide.

CSS and the programme

Term	What it means
CSS	Comparison Shopping Service. A Google-certified partner that places Shopping ads for merchants.
CSS Center	The Google account a CSS operates from, distinct from Merchant Center.
Google Shopping Europe	Google’s own CSS, and the default every merchant starts in.
Premium CSS Partner	A tier for partners meeting higher volume, service and compliance standards.
Whitelabel CSS	Operating as a CSS Partner under your own brand on a provider’s infrastructure.
The "By" line	The attribution under a Shopping ad naming the CSS that placed it.
Association	The link between a Merchant Center account and a CSS.

Term	What it means
Standard Shopping	A campaign type buying Shopping placements only, with product-level control.
Performance Max	A campaign type buying across all Google inventory from one budget.
PMax	Performance Max.
Asset group	The creative unit in Performance Max, the rough equivalent of an ad group.
Listing group	How products are segmented inside a Performance Max campaign.
Product group	How products are segmented inside a Standard Shopping campaign.
Smart Bidding	Google’s automated bidding strategies, optimising a stated objective.
ROAS	Return on ad spend. Revenue divided by cost.
Impression share	The share of eligible auctions in which your ad appeared.
Local Inventory Ads	Shopping ads showing availability at a specific store.
Free listings	Unpaid product listings across Shopping surfaces.

Term	What it means
Merchant Center	Where product data is submitted, validated and monitored.
Primary feed	The main source of product data for an account.
Supplemental feed	A feed that adds to or overrides attributes in the primary feed.
Content API	The programmatic interface for near real-time product updates.
GTIN	Global Trade Item Number. The barcode; EAN in Europe, UPC in North America.
MPN	Manufacturer Part Number. Unique within a brand, not globally.
item_group_id	The attribute tying variants of one product together.
google_product_category	The item’s place in Google’s own product taxonomy.
product_type	The item’s place in your own category structure.
Disapproval	An item rejected by Merchant Center and therefore not served.
Feed enrichment	Deriving and filling missing product attributes at catalogue scale.
PIM	Product Information Management. The system of record for product data.

Term	What it means
Packshot	A product photographed alone on a plain background.
Lifestyle image	A product shown in a scene or in use.
Image-to-video	Generating a short clip from a still photograph.
EU AI Act	Regulation (EU) 2024/1689, whose transparency rules apply from 2 August 2026.
Article 50	The transparency obligations, including marking of synthetic content.
Provider	Whoever develops and offers the AI system.
Deployer	Whoever uses it, such as a merchant generating its own imagery.
Deep fake	Generated content resembling real people, places or events, appearing authentic.
C2PA	A provenance standard embedding a signed manifest of how a file was made.
Content Credentials	The consumer-facing name for C2PA provenance data.
IPTC Digital Source Type	A metadata field naming the origin of an image.
Invisible watermark	A provenance signal carried in the pixels themselves.