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1. Zuckung, (Ger., contraction). 2. Symbol for atomic number.


zero; zone.


(ză-fir′loo-kast″, za″fir-loo′kast) A leukotriene inhibitor used to treat asthma.

Zahn line

(zon) [Frederick W. Zahn, Ger. pathologist, 1845–1904] One of the transverse whitish marks on the free surface of a thrombus made by the edges of layered platelets.

Zahorsky disease

(ză-hor′skē) Roseola.


(zan′tak″) Ranitidine.


(zar) A culture-bound illness specific to Northern Africa and the Middle East in which people are possessed by evil spirits. The disease has characteristics reminiscent of the Western illness known as dissociative identity disorder.

Zavanelli maneuver

(zav″ă-nel′ē) [William Angelo Zavanelli, U.S. obstetrician and gynecologist, b. 1926] In obstetrics, the manual return of the head of a partially born fetus with intractable shoulder dystocia to the vagina. This is followed by cesarean section.

Z disk

SEE: under disk.

Z drugs

Drugs used to treat insomnia including zaleplon, zolpidem, and zopliclone.




(zē′ă) [Gr. zeia, (coarse) wheat, spelt] Maize or corn.


(zē″ă-zan′thĭn) [Zea, the genus name for corn (maize) + xantho- + -in] A pigmented antioxidant (a member of the carotenoid family) that is found in broccoli, corn, leafy green vegetables, and squash. Consumption of zeaxanthin-rich foods has been associated with a decreased risk of age-related macular degeneration.


(zē′ĭn) [Zea, the genus name for corn (maize) + -in] A protein obtained from maize. It is deficient in tryptophan and lysine.


(zī′sē-ăn) Pert. to something originally described by Eduard Zeis.


(tsīt′gā″bĕr, zīt′gā″bĕr) [Ger. Zeitgeber, timekeeper] Any of the mechanisms in nature that keep internal biological clocks synchronized (entrained) with the environment. Zeitgebers can be physical, involving light or temperature, e.g., sunrise, sunset, or social, involving regular activities, e.g., consistent mealtimes.


(tsīt′gīst″) [Ger. Zeitgeist, spirit of the time] The spirit of the people or the dominant trend of thought at a particular time.

Zellweger syndrome

(zel′weg″ĕr) [Hans Zellweger, Swiss-born U.S. pediatrician and geneticist, 1909–1990] An autosomal recessive leukodystrophy caused by the reduction or absence of functional peroxisomes in a patient’s cells. The syndrome is associated with impaired brain development, reduction in central nervous ...

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