There are many ways to create a glossary of terms in WordPress. They can be divided into two: manually and automatically.
In this guide we’ll show how to do it manually. As an example, we will create a simple glossary with four WordPress-related terms.
Read all the instructions https://www.cminds.com/cm-faq-question/wordpress/create-wordpress-glossary-without-plugin/
Easily create a glossary with the Tooltip Glossary plugin https://www.cminds.com/wordpress-plugins-library/tooltipglossary/