Main Entry: let·down

Pronunciation: \ˈlet-ˌdau̇n\

Function: noun

Date: 1768

1 a : discouragement, disappointment <his latest novel is a letdown> b : a slackening of effort : relaxation
2 : the descent of an aircraft or spacecraft to the point at which a landing approach is begun
3 : a physiological response of a lactating mammal to suckling and allied stimuli whereby previously secreted milk from the acini is expelled into ducts and drawn through the nipple