How do synonyms work in Elastic Search for Magento 2?
Synonyms allow you to connect different words so they will give the same results. For example, connecting the words “laptop, notebook, netbook” will allow users to see all the laptop-type products despite the word they have chosen for the search.
To build a dictionary of synonyms, navigate to Admin Panel → System → Manage Synonyms.
Note: please, keep in mind that word combinations and special characters are not supported and will be ignored (eg.: laptop$%^, thin laptop).