#glossary #Amazon Ads #KDP #ACOS #definitions

Amazon Ads Glossary for KDP Authors

James Whitfield · July 23, 2026 · 6 min read

This is a plain-English glossary of the Amazon Ads terms every KDP author runs into. Bookmark it and come back whenever a term in the dashboard is unclear.

Core metrics

ACOS (Advertising Cost of Sales): ad spend as a percentage of ad sales. Lower is more efficient. See the full explainer.
ROAS (Return on Ad Spend): ad sales divided by ad spend. The inverse of ACOS. A 25% ACOS is a 4x ROAS.
TACOS (Total ACOS): ad spend as a percentage of total sales, including organic. Shows how dependent you are on ads.
Break-even ACOS: the ACOS at which an ad costs exactly what the sale earns. Equals your margin.
CTR (Click-Through Rate): clicks divided by impressions. How appealing your ad is.
CVR (Conversion Rate): orders divided by clicks. How well your book page sells.

Campaign terms

Sponsored Products: ads that promote a single book in search and on product pages. See SP vs SB.
Sponsored Brands: banner ads promoting a brand or group of books.
Manual vs Automatic targeting: manual means you pick keywords; automatic means Amazon picks for you.
Match type: how closely a search must match your keyword (exact, phrase, broad).
Placement: where the ad shows (top of search, rest of search, product pages). See placements.

Keyword terms

Keyword: a term you target. See keyword research.
Search term: what a shopper actually typed. See the search terms report.
Negative keyword: a term you block your ad from showing on. See negatives.
Bid: the maximum you pay for a click. See how to bid.

FAQ

What is the difference between a keyword and a search term? A keyword is what you choose to target. A search term is what a shopper actually typed. One broad keyword can match many search terms.

What is the difference between ACOS and TACOS? ACOS measures spend against ad sales only. TACOS measures spend against total sales including organic. A falling TACOS means your book increasingly sells on its own.

Do I need to know all of these to start? No. ACOS, keyword, bid and negative keyword are enough to run your first campaign. The rest you pick up as you go.