The text that is used as a hyperlink to another page is called “anchor text.”
In this example:
I really like the science at the Chicago Field Museum.
The text “science at the Chicago Field Museum” links to the Chicago Field Museum’s website. The text “science at the Chicago Field Museum” is the anchor text.
Google and Bing read the anchor text as a signal to tell them what the link is about. Writing good anchor text for both outbound links and internal links is important for SEO, though the level of importance of anchor text may be decreasing as the search engines strive to become more efficient.
Most importantly, anchor text is a vital way to let the user know what your link is. You don’t want your users to be confused, do you?