What it means
AAP (Amazon Advertising Platform) is the former name of today's Amazon DSP — Amazon's platform for programmatic display, video, and audio advertising on and off Amazon. In 2018, Amazon consolidated its ad products AAP, AMS (Amazon Marketing Services), and AMG (Amazon Media Group) under the Amazon Advertising umbrella (now Amazon Ads); AAP became the Amazon DSP. Today the term only appears in older documents and legacy systems — what's meant is practically always the DSP.