thanks for explainingIt means that you supply a quoted list of keywords and the search will only return results that match a minimum # of keywords from that group (regardless of which ones specifically) -- e.g. "A B C" /2 is effectively (A and B) OR (A and C) OR (B and C).
A quorum of /1 is equal to OR while a quorum of /x (x being the full number of terms) is equal to AND.
(The term itself originates from law where a quorum is the minimum number of persons from a group required to be present to discuss and vote on topics, like passing bills and legislation)
For a more advanced example, there are at least ten different spellings for "gryphon" (counting both singular and plurals) and just 3 on FA happen to use specify seven of them, one of them even specifying eight terms (which you can easily spot in its list of keywords).
Though this seems like a feature with rather limited usecases....