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Medical Dictionary


ζ, upper case Ζ
  • zeta, sixth letter of the Greek alphabet
  • the sixth in a series, e.g., the sixth carbon from a functional group
  • electrokinetic potential
  • amino acid that is either glutamic acid, glutamine, or a substance that yields glutamic acid on acid hydrolysis of peptides
  • atomic number
  • benzyloxycarbonyl (carbobenzoxy-)
  • carbobenzoxyabbreviation for zepto-
  • impedance
  • zusammen
the left-handed uncommon form of double helix DNA in which the chains twist up and to the left around the front of the axis of the helix and which has 12 base pairs in each helical turn and one groove on the external surface

z distribution
a probability density function and especially a normal distribution that has a mean equal to zero and a standard deviation equal to one and that is used especially in testing hypotheses about means or proportions of samples drawn from populations whose population standard deviations are known

Z line
any of the dark thin bands across a striated muscle fiber that mark the junction of actin filaments in adjacent sarcomeres

Z particle
a neutral elementary particle about 90 times heavier than a proton that along with the W particle is a transmitter of the weak force, also called Z0, or Z0 particle

Alejandro, Uruguayan-U.S. chemist and biochemist, *1923. See Z. system.

zafirlukast (za-fir-loo′kast)
A blocker of leukotriene D4 and E4 (LTD4 and LTE4) components of a slow-reacting substance of anaphylaxis (SRSA); used for the prophylaxis of asthma attacks.

John, 19th century anatomist's assistant in Edinburgh. See Z. ligament.

Friedrich W., German pathologist, 1845–1904. See Z. infarct, lines of Z., under line, striae of Z., under stria.

Leo von, 20th century German physician. See generalized pustular psoriasis of Z..

zanamivir (zan-am′i-vir)
An agent that inhibits neuraminidase of influenza virus.

Julius, Austrian physician, 1867–1942. See Z. counting chamber.

William, 20th century U.S. obstetrician. See Z. maneuver.

zea (ze′a)
The styles and stigmas of Z. mays (family Gramineae), Indian corn; formerly used as a diuretic and antispasmodic. SYN: cornsilk. [Mod. L. maize]

zearalenone (ze′a-ral-en-on)
One of the resorcylic acid lactones; used in veterinary medicine as an anabolic.

zeatin (ze′a-tin)
A cytokinin first isolated from kernels of sweet corn. SYN: maize factor.

zeaxanthin (ze′a-zan′thin)
A carotene found in corn, fruits, seeds, and egg yolk; isomeric with xanthophyll. SYN: zeaxanthol. [Mod. L. Zea, Indian corn, fr. L. zea, grain + G. xanthos, yellow, + -in]

zeaxanthol (ze-a-za-thol)
SYN: zeaxanthin.

Pieter, Dutch physicist and Nobel laureate, 1865–1943. See Z. effect.

Abbreviation for zero end-expiratory pressure.

zein (ze′in)
A prolamine present in maize; it lacks chiefly the amino acids l-tryptophan and l-lysine and is also low in cysteine content. It is the main storage protein in maize.

Eduard, Dresden ophthalmologist, 1807–1868. See Z. glands, under gland, zeisian sty.

zeisian (zis′e-an)
Relating to or described by Eduard Zeis.

Zeitgeist (zit′gist)
In psychology, the climate of opinion, conventions of thought, covert influences, and unquestioned assumptions that are implicit in a given culture, the arts, or science at any point in time, and in which the individual operates and thus is influenced. [Ger. zeit, time, + geist, spirit]

Hans U., U.S. pediatrician, 1909–1990. See Z. syndrome.

zelophobia (ze-lo-fo′be-a)
Morbid fear of jealousy. [G. zelos, zeal, + phobos, fear]

zelotypia (ze-lo-tip′e-a)
Excessive zeal, carried to the point of morbidity, in the advocacy of any cause. [G. z.; rivalry, envy, fr. zelos, zeal, + typto, to strike]

Friedrich A., German pathologist, 1825–1898. See Z. degeneration, Z. diverticulum, Z. fixative, Z. paralysis, formol-Z. fixative.

zeolite (ze′o-lit)
A naturally occurring hydrated sodium aluminum silicate, Na2O&chmpnt;Al2O3&chmpnt;(SiO2)x&chmpnt;(H2O)x, used for softening of hard water by exchanging its Na+ for the Ca2+ of the water; thus z. is an ion exchanger. Some synthetic ion exchangers are termed synthetic zeolites, although there is no chemical relationship.

zeoscope (ze′o-skop)
A device for determining the alcoholic content of a liquid by ascertaining its exact boiling point. [G. zeo, to boil, + skopeo, to examine]

zepto- (z)
Prefix used in the SI and metric systems to signify submultiples of 10−21.

zero (ze′ro)
1. The figure 0, indicating the absence of magnitude, or nothing. 2. In thermometry, the point from which the figures on the scale start in one or the other direction; in the Celsius and Réaumur scales, z. indicates the freezing point for distilled water; in the Fahrenheit scale, it is 32° below the freezing point of water. [Sp. fr. Ar. sifr, cipher] absolute z. the lowest possible temperature, that at which the form of translational motion constituting heat is assumed no longer to exist, determined as −273.15°C or 0 kelvin.

zero gravity (ze-ro-grav′i-te)
A physical state existing in space or at a time in flight when the centrifugal thrust of a parabolic glide or turn exactly counteracts the force of gravity.

zetacrit (za′ta-krit)
The packed cell volume produced by vertical centrifugation of blood in capillary tubes, allowing controlled compaction and dispersion of red blood cells; read with a hematocrit to produce the zeta sedimentation ratio.

SYN: fibronectins.

zeugmatography (zoog-ma-tog′ra-fe)
Term coined by Lauterbur in 1972 for the joining of a magnetic field and spatially defined radiofrequency field gradients to generate a two-dimensional display of proton density and relaxation times in tissues, the first nuclear magnetic resonance image. [G. zeugma, that which joins together]

zidovudine (zi-do′voo-den)
A thymidine analog that is an inhibitor of in vitro replication of HIV virus, the causative agent of AIDS and ARC, and is used in the management of these diseases. SYN: azidothymidine.

Samuel L., U.S. ophthalmologist, 1861–1926.

Georg T., German psychiatrist, 1862–1950. See Z.-Oppenheim disease.

Franz, German bacteriologist, 1857–1926. See Z. stain, Z.-Neelsen stain.

Hans R.P., German pathologist, 1865–1939. See Z. dots, under dot, Z. stippling.

Leslie, U.S. physician, *1915. See Z. syndrome.

Franz, Swiss physician, 1858–1932. See Z. atrophy.

Karl W., German histologist, 1861–1935. See Z. corpuscle, Z. granule, Z. elementary particle, polkissen of Z..

Wilhelm, German physician, *1910. See Z. reaction, Z. test.

zinc (Zn) (zingk)
  • A metallic element, atomic no. 30, atomic wt. 65.39; an essential bioelement; a number of salts of z. are used in medicine; a cofactor in many proteins.
  • z. acetate: an emetic, styptic, and astringent.
  • z. caprylate: a topical antifungal compound.
  • z. chloride: ZnCl2;formerly used as a caustic for the removal of cutaneous cancers, nevi, etc., and in weak solution in the treatment of gonorrhea and conjunctivitis. SYN: butter of z..
  • z. gelatin: z. oxide, gelatin, glycerin, and purified water; used topically as a protectant.
  • z. iodide: ZnI2;has been used as an antiseptic and astringent.
  • medicinal z.: peroxide a mixture of z. peroxide, z. carbonate, and z. hydroxide; a topical disinfectant, astringent, and deodorant.
  • z. oxide: ZnO;used as a protective in ointment, as a dusting powder; also used in paint as a substitute for lead carbonate. SYN: flowers of z., z. white.
  • z. oxide and eugenol: used as a base material beneath metallic dental restorations and as a temporary filling material or impression material; setting and hardening result from complex reactions between the powder and the eugenol.
  • z. permanganate: action is similar to that of potassium permanganate, but more astringent; used in urethritis, by injection or douche in a 1:4000 solution.
  • z. peroxide: ZnO2;a yellowish white powder, insoluble in water and decomposed by acids; used in pharmaceutic preparations. SYN: z. superoxide.
  • z. phenolsulfonate: used as an intestinal antiseptic and locally as an astringent in chronic inflammation of the mucous membranes. SYN: z. sulfocarbolate.
  • z. phosphide: Zn3P2;used as a bait poison for the extermination of rats and mice.
  • z. stearate: a z. compound with variable proportions of stearic and palmitic acids; a water-repellent, protective agent used in powders and ointments in the treatment of eczema, acne, and other skin diseases.
  • z. sulfate: used as a local astringent in the treatment of gonorrhea, indolent ulcers, conjunctivitis, and various skin diseases, and internally as an emetic.
  • z. sulfocarbolate: z. phenolsulfonate.
  • z. superoxide: z. peroxide.
  • z. undecylenate, z. undecenoate: the z. salt of undecylenic acid; used in the treatment of fungal and other affections of the skin, including psoriasis.
  • z. white: z. oxide.
zinc-65 (65Zn)
A radioactive zinc isotope that decays mainly by K-capture with a half-life of 243.8 days; used as a tracer in studies of zinc metabolism.

zinciferous (zing-kif′er-us)
Containing zinc.

zincoid (zing′koyd)
Relating to or resembling zinc. [G. eidos, resemblance]

zingiber (zin′ji-ber)
SYN: ginger.

Johann G., German anatomist, 1727–1759. See Z. artery, Z. vascular circle, Z. corona, Z. ligament, Z. membrane, Z. ring, Z. tendon, Z. zonule.

Hans, U.S. bacteriologist and immunologist, 1878–1940. See Brill-Z. disease.

zirconium (Zr) (zir-ko′ne-um)
A metallic element, atomic no. 40, atomic wt. 91.224; widely distributed in nature, but never found in quantity in any one place. [zircon, a mineral, fr. Ar. zarkun, cinnabar, Pers, zargun, goldlike]

zirconium oxide
Used as a coating for the skin in dermatologic pharmaceuticals and as a pigment in paints.

Abbreviation for zeptometer.

Symbol for zinc.

Abbreviation for zinc-65.

Symbol for microliters of oxygen taken up per hour by 108 spermatozoa; can vary as a function of temperature.

See zoo-.

zoanthropic (zo-an-throp′ik)
Relating to or marked by zoanthropy.

zoanthropy (zo-an′thro-pe)
A delusion that one is an animal, such as a dog. [G. zoon, animal, + anthropos, man]

zoetic (zo-et′ik)
Relating to life. [G. zoe, life]

zoic (zo′ik)
Relating to living things; having life. [G. zoikos, relating to an animal]

zoite (zo′it)
SYN: sporozoite. [G. zoon, animal]

Robert M., U.S. surgeon, *1903. See Z.-Ellison syndrome, Z.-Ellison tumor.

Johann F., German physicist, 1834–1882. See Z. lines, under line.

zolpidem (zol′pe-dem)
A sedative/hypnotic drug useful for treating anxiety and resembling benzodiazepines in its pharmacology but differing somewhat in chemical structure. Unlike benzodiazepines, z. lacks prominent anticonvulsant properties, and less tolerance may develop with its use.

zomepirac sodium (zo-me-pir′ak)
An analgesic anti-inflammatory agent, no longer marketed.

zona, pl .zonae (zo′na, zo′ne)
  • zone.
  • herpes zoster
  • z. arcuata: arcuate zone.
  • z. ciliaris: ciliary zone.
  • z. corona: costal fringe.
  • z. dermatica: a ridge of thickened skin surrounding the protrusion in spina bifida.
  • z. epithelioserosa: the membranous ring, within the z. dermatica, surrounding the protrusion in spina bifida.
  • z. externa: medullae renalis: outer zone of renal medulla.
  • z. fasciculata: the layer of radially arranged cell cords in the cortical portion of the suprarenal gland, between the z. glomerulosa and z. reticularis; secretes cortisol and dehydroepiandrosterone.
  • z. glomerulosa: the outer layer of the cortex of the suprarenal gland just beneath the capsule; secretes aldosterone.
  • z. hemorrhoidalis: hemorrhoidal zone.
  • zonae hypothalamicae: zones of hypothalamus, under zone.
  • z. incerta: a flat, obliquely disposed plate of gray matter in the subthalamic region situated between the thalamic fasciculus (tegmental field H1 of Forel) and the lenticular fasciculus (tegmental field H2). Medially, cells of this nucleus are adjacent to the prerubral area (tegmental field H) and, laterally, they are continuous with the reticular nucleus of the thalamus. Z. i. is a derivative of the ventral thalamus; it receives afferents from the precentral motor cortex and the cerebellum.
  • z. interna medullae renalis: inner zone of renal medulla.
  • z. lateralis: lateral zone. See zones of hypothalamus, under zone.
  • z. medialis: medial zone. See zones of hypothalamus, under zone.
  • z. medullovasculosa: the fissured segment of the spinal cord that dorsally closes the sac in meningomyelocele.
  • z. ophthalmica: herpes zoster in the distribution of the ophthalmic nerve.
  • z. orbicularis (articulationis coxae): fibers of the articular capsule of the hip joint encircling the neck of the femur, aka orbicular zone of hip joint, ring ligament, zonular band.
  • z. pectinata: pectinate zone.
  • z. pellucida: an extracellular coat, rich in glycoprotein, surrounding the oocyte; it contains microvilli of the oocyte and cellular processes of follicular cells and appears homogeneous and translucent under the light microscope, aka pellucid zone.
  • z. perforata: foramina nervosa, under foramen.
  • z. periventricularis: periventricular zone. See zones of hypothalamus, under zone.
  • z. pupillaris: pupillary zone.
  • z. radiata: z. striata.
  • z. reticularis: the inner layer of the cortex of the adrenal gland, where the cell cords anastomose in a netlike fashion.
  • z. striata: the thickened cell membrane of the ovum in forms, such as certain amphibia, in which it appears radially striated under the light microscope; with the electron microscope the striations can be seen to be microvilli, aka membrana striata, striated membrane, z. radiata.
  • z. tecta: arcuate zone.
  • z. transitionalis analis: anal transitional zone.
  • z. vasculosa: vascular zone.


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