Thesaurus refers to collections of terms that are thematically related to each other.
The word synonym comes closest to the meaning, whereby synonymous words are words with comparable content. Such term vocabularies or keyword catalogs exist in all technical, economic, scientific, medical, social, psychological and other life-related fields.
Thesauruses used an algorithm for determining a replacement word. The term is used in searchengine optimization( SEO) to determine the keywords that are most frequently entered by users in search queries.