u·bi·qui·none 
(y′bĭ-kwĭ-nōn, -kwĭnōn′)
(y′bĭ-kwĭ-nōn, -kwĭnōn′)n.
Any of a family of fat-soluble quinone compounds that are found in the membranes of eukaryotic cells, especially in mitochondria, and serve as electron carriers in cellular respiration and other processes. Also called coenzyme Q.
[Blend of UBIQUITOUS (from its widespread distribution) and QUINONE.]