The most recent term was secondary meaning, which is defined as:
law, a mark that is not inherently distinctive
becomes protected after developing a "secondary meaning": great public
recognition through long use and exposure in the marketplace. For
example, though first names are not generally considered inherently
distinctive, Ben & Jerry's Ice Cream has become so well known that
it is now entitled to maximum trademark protection.
No one guessed this time around.
Today's term, as suggested by Harvey Randell of the New York Public Personnel Law blog, is:
the doctrine of legislative equivalency.
As always, no dictionaries, please.