Discount codes from Amazon may be accessible for particular items or categories, or they may be available for all items or the entire store. Depending on the type of code and the campaign, the codes may not always be available. While some codes might only apply to select things on the internet, like electronics or clothing, others might apply to everything.
Always read the code's terms and conditions to determine what things it applies to. Searching for amazon discount codes that are accessible for particular products or categories on the website is what is meant when "amazon discount codes" are used in reference to certain products or categories.