dry rot

• dryrot
• dry-rot

dry rot (uncountable)

1. The crumbly, friable decayed portions of wooden members of buildings, especially at or below grade, usually caused by a fungal infection.

   1836 They are, for the most part, low-roofed, mouldy rooms, where innumerable rolls of parchment, which have been perspiring in secret for the last century, send forth an agreeable odour, which is mingled by day with the scent of the dry-rot, and by night with the various exhalations which arise from damp cloaks, festering umbrellas, and the coarsest tallow candles. — Charles Dickens, The Pickwick Papers.

2. (figuratively) Any progression of decay, corruption, or obsolescence.

   1952 Therefore I am like a moth to Ephraim, and like dry rot to the house of Judah. Hosea 5:12, RSV

   1919 But the victims of moral dry rot held up their hands in rebuke and one of the city judges wept metaphorical tears of chagrin that the Police should engage in the awful crime of enticing a youth to commit crime. — William Roscoe Thayer, Theodore Roosevelt: An Intimate Biography Chapter 7.

3. (phytopathology) A fungal infection which affects plants, in particular potatoes.