Catastrophe (Gk. katastrephein "to turn around") was in ancient Greek tragedies the solution of the plot. Nowadays it is used to describe a disaster on a larger scale, destroying most or all means to fight it, including the extinction of whole societies. ...

The Univeristy of Delaware's Disaster Research Center differentiates disasters from emergencies and catastrophes as follows:

• Emergency: An event that may be managed locally without the need of added response measures or changes to procedure.
• Disaster: An event that,

1. involves more groups who normally do not need to interact in order to manage emergencies
2. requires involved parties to relinquish the usual autonomy & freedom to special response measures and organizations
3. changes the usual performance measures, and
4. requires closer operations between public and private organizations.

• Catastrophe: An event that,

1. destroys most of a community
2. prevents local officials performing their duties
3. causes most community functions cease, and
4. prevents adjacent communities from providing aid. [1]

In the insurance field, a catastrophe is a disaster beyond expectations. For instance, the insurance industry can use catastrophe modeling to calculate the expected damage from hurricanes in a specific location for a particular year. An emergency is a situation that poses an immediate threat to human life or serious damage to property. ... Insurance, in law and economics, is a form of risk management primarily used to hedge against the risk of potential financial loss. ... Catastrophe modeling is the process of using computer-assisted calculations to estimate the losses that could be sustained by a portfolio of properties due to a catastrophic event such as a hurricane or earthquake. ...

In the field of sociology it is defined as social change of an outstanding radical and rapid character, with highly magical explanations by victims and others. Social interactions of people and their consequences are the subject of sociology studies. ... Social change refers to acts of advocacy for the cause of changing society in a positive way. ...

As a technical, and a computer-related term, "catastrophic failure" usually refers to a failure within a system which leads to failure of the system as a whole.

In mathematics, catastrophe theory studies how the behaviour of dynamical systems can change drastically with variations in certain parameters. Catastrophe theory is a branch of mathematics that deals with dynamical systems and was originated with the work of the French mathematician René Thom in the 1960s. ... A dynamical system is a concept in mathematics where a fixed rule describes the time dependence of a point in a geometrical space. ...