Noun

(en noun)

(uncountable) The emotion felt when a strongly held expectation is not met.

Choking back his disappointment after his own team's splendid wins against Liverpool and Aston Villa, he said: "I've got to be humble and say we were beaten by a very good side."'' — ''Today , News Group Newspapers Ltd, 1992

(countable) A circumstance in which a strongly held expectation is not met.

* {{quote-news

, year=2012 , date=May 5 , author=Phil McNulty , title=Chelsea 2-1 Liverpool , work=BBC Sport citation , page= , passage=For Liverpool, their season will now be regarded as a relative disappointment after failure to add the FA Cup to the Carling Cup and not mounting a challenge to reach the Champions League places.}}

As the disappointments crowded in — the economy, Rhodesia, strife within the trade-union movement — tried the expedient of a semi-formal inner Cabinet, or Parliamentary Committee, as he misleadingly liked to call it.'' — ''Cabinet , Hennessy, Peter, Basil Blackwell Ltd, 1990

Noun

(en noun)

Any large and disastrous event of great significance.

(insurance) A disaster beyond expectations

(narratology) The dramatic event that initiates the resolution of the plot in a tragedy.

(mathematics) A type of bifurcation, where a system shifts between two stable states.