A link at the end of every secondary entry to see another entry is called a cross-reference. The cross-reference tells you where the main entry for a word's synonym group is located. No matter which member of a synonym group you used to begin your search, you can always find your way to the entry that has the lists of all the synonyms and any related words, phrases, near antonyms, or antonyms.

If there is more than one sense referred to in the cross-reference, the cross-reference will also include a sense number. If the word has more than one numbered homograph, the cross reference will send you to the right homograph number as well:

Entry Word: pain
Function: verb
Text: to feel or cause physical pain <my poor head was paining so from all that racket> -- see HURT 1

Entry Word: ranking
Function: noun
Text: 1 a scheme of rank or order <in one ranking of the best places to live, San Francisco surpassed all the other cities in the U.S.> -- see 3SCALE 1

If a word appears as more than one part of speech, the cross-reference will send you to the same part of speech as the word you looked up. The cross-reference in the ranking example above tells you that the main entry where you will find ranking as a member of the synonym group with the shared meaning "a scheme of rank or order" is at sense 1 of the noun entry 3scale:

Entry Word: 3scale
Function: noun
Text: 1 a scheme of rank or order <a student who scored very highly on a standard intelligence scale>
Synonyms: graduation, ladder, ordering, ranking