X-disease

//ˈɛks.dɪ.ziz// name

name ·Rare ·Advanced level

Definitions

Proper Noun
  1. 1
    Any of various diseases of plants or animals whose origin was at first a mystery, especially:; Hyperkeratosis in cattle.

    "In making a diagnosis of X-disease, one must consider the insidious onset, slow course, and number of animals affected."

  2. 2
    Any of various diseases of plants or animals whose origin was at first a mystery, especially:; A disease of stone fruits caused by a form of mycoplasma.

    "Transmission of X-disease was more erratic with peach than with chokecherry buds, possibly because only low titers of the X-disease mycoplasma-like organisms (MLO) are present in infected peach trees during most of the year."

Example

More examples

"In making a diagnosis of X-disease, one must consider the insidious onset, slow course, and number of animals affected."

Etymology

From the convention of using "X" as a variable to stand for something unknown.

Data sourced from Wiktionary, WordNet, CMU, and other open linguistic databases. Updated March 2026.