inverting search results
Search results may be inverted. An inverted search retrieves all entries which do not contain the search term.
Inversion is indicated by placing the ^ sign before a search term. So, ^slave* would find all entries which did not contain the words slave or slaves, and ^\PLC would retrieve those without place-names.
As with the - operator, you cannot invert a term in a list of alternatives: it is not valid to search for Goats|^Sheep.