Turbo snippets are the pop-ups you see when you move your mouse over a hyperlink. Usually you will get a short explanation about the page the internal or external backlink refers to.
Turbo snippets thus offer the visitor information without him or her having to leave the page. This improves the user experience and the abandonment rate.
Turbo snippets are not only used in search results, but also on a destination page, a landing page or in e-mail marketing.
Besides turbo snippets, there are also featured snippets and rich snippets.