The reason why Amazon included in suggested search engines is because they using with Amazon's A9 Algorithm which is an product ranking algorithm composed with direct and indirect factors that match user's need when they searching the queries of the product that might be purchased. If you want to set your search primarily for certain links, you may go here:

1. about:preferences#home

2. Then click the Homepage and new windows to set your custom url etc: " https://blackwells.co.uk/bookshop/home" or using bookmarks to open them instead of typing the website link in your choice

3. So, when you open a new home page or windows you can directly access to that link that you customized...

4. Hope this forum can help you to answer your question as well if my answer doesn't help much "https://support.mozilla.org/en-US/questions/1293669"

Hope I answer your question and Have a nice day~

Actually you can add any custom search keywords. Go to the website you would like to add as a custom search right-click the search bar and select "add a keyword for this search". This will add a bookmark. Now type in the keyword you want to use and a name for the bookmark. Now for example if you typed "book" as your keyword you can type book <your search> in the address bar and it will take you directly to the site.

Read the docoumnatation here

Many of us add stores and shops to our search engine choices.

How, please?

How, please?

Earlier there was a link to this article about adding website search boxes as keyword-enabled bookmarks that you can search through the address bar. You could try this and see what you think:

How to search IMDB, Wikipedia and more from the address bar

Adding a picture: