The index meta keywords feature offers the ability to include the contents of a page’s meta keywords tag in your AddSearch index. It is useful to enable this feature if pages contain meaningful keywords that would further help your users when searching your site.
Meta keywords are given greater weight than the regular text found on a page.
You can toggle on the “index meta keywords” option via the Domains & crawling section of your dashboard.
Please note that for changes in this setting to take effect, a recrawl is required.