What is Inverted minors?

Inverted minors refers to a treatment introduced by the Kaplan–Sheinwold bidding system for the popular card game bridge. The original structure of Precision, another bidding system, also employed inverted minors over a 1♦ opening. However, the treatment is no longer restricted to users of these bidding systems. although partnerships that use a Short club system tend also to use the convention only after a 1♦ opener.