Google Ads glossary
Short definitions of feed terms, including the free product listing, and of measurement terms. The free audit covers Google Ads only.
WeAdU · Updated 3 October 2026
What is a GTIN in a multi-brand feed?
A GTIN (Global Trade Item Number) is the trade item number assigned by the manufacturer: UPC, EAN, JAN or ISBN. In a multi-brand feed, the gtin attribute receives that number and not the store's own code: submit it only when it is certain, and do not guess it.
What is an MPN in Google Merchant Center?
An MPN (Manufacturer Part Number) is the manufacturer's reference for a product. In Google Merchant Center, the mpn attribute receives that reference: it is required when the manufacturer assigned no GTIN, and optional for a custom item or one with no clear reference.
What is a brand exclusion on Performance Max?
A brand exclusion list, on Performance Max, is a list of brands from Google Ads, applied as an exclusion on the campaign. Ads no longer trigger on queries associated with those brands.
What is an unavailable product page?
An unavailable product page, in Google Merchant Center, is a landing page Google cannot open. While that page stays unreachable, the product stops serving: it is not an out-of-stock status.
What is break-even ROAS?
Break-even ROAS is the multiple at which gross margin covers Google Ads spend. The formula published on the audit page is: break-even ROAS = 1 ÷ gross margin, before overhead.
What is impression share in Google Ads?
Impression share is the percentage of impressions recorded out of the eligible impressions. It is not CTR, which compares clicks with impressions already received.
What is a free product listing (free listing)?
A free product listing (free listing) is a way to show a product on Google at no cost, with the offer details, from Merchant Center. If the product is eligible, it may appear on Search, Images, Lens, YouTube, Gemini, the Shopping tab, Maps and the products module on a Business Profile: the help points to product pages, not a homepage, a shipping or returns page, or a category page.