
In the game of contract bridge, a convention is an agreed-upon meaning for a call (a bid, double or redouble, or a pass) during the auction phase of the hand. Often, the inventor of the convention gives it a name; some widespread conventions got a name after their (perceived) authors.
Conventional opening leads and discards may also be used. The term, however, usually denotes just a bidding convention.
♣
Bidding system is set of agreements and conventions in bidding between two partners in contract bridge. A bidding system defines the meaning of every possible bid by each partner, and presents a codified language which allows the partners to find out about each other's holdings and determine the correct contract.
The IRON GATES Region Museum

A crisis (plural: crises) may occur on a personal or societal level. It may be a traumatic or stressful change in a person's life, or an unstable and dangerous social situation, in political, social, economic, military affairs, or a large-scale environmental event, especially one involving an impending abrupt change. More loosely, it is a term meaning 'a testing time' or 'emergency event'.