Definitions provided by:
Skin, Hair and Nails Glossary

Terms used to explain Skin, Hair and Nails can sometimes be confusing. To help you fully understand the articles and features related to this very important health topic, we have compiled a glossary of terms that can help.

Filter by Topic:


Pronunciation: \ˈa-kyu-ˌtān\

Function: trademark
used for a preparation of isotretinoin


Pronunciation: \ˈak-nē\

Function: noun
: a disorder of the skin caused by inflammation of the skin glands and hair follicles; specif: a form found chiefly in adolescents and marked by pimples esp. on the face


Pronunciation: \ˌal-kə-ˈhol-ik, -ˈhäl-\

Function: adjective

1 a: of, relating to, or caused by alcohol <alcoholic[1] hepatitis>
b: containing alcohol
2: affected with alcoholism


Pronunciation: \ˈal-ər-jē\

Function: noun
pl -gies

1: altered bodily reactivity (as hypersensitivity) to an antigen in response to a first exposure <his bee-venom allergy may render a second sting fatal>
2: exaggerated or pathological reaction (as by sneezing, respiratory embarrassment, itching, or skin rashes) to substances, situations, or physical states that are without comparable effect on the average individual
3: medical practice concerned with allergies

Ankylosing Spondylitis

ankylosing spondylitis
Function: noun
: rheumatoid arthritis of the spine —called also Marie-Strümpell disease, rheumatoid spondylitis


Pronunciation: \-bī-ˈät-ik; -bē-\
Function: adjective
1: tending to prevent, inhibit, or destroy life
2: of or relating to antibiotics or to antibiosis


Function: noun
: any of various compounds that oppose the actions of histamine and are used esp. for treating allergic reactions (as hay fever), cold symptoms, and motion sickness


Pronunciation: \bak-ˈtir-ē-ə\

Function: noun

1: see: bacteriumnot usu. used technically<caused by a bacteria[2] borne by certain tiny ticks Wall Street Jour.> <a single bacteria[2]—there are roughly 200 in each cough—apparently can infect a person Cheryl Clark>
2plcap: a domain in the system of classification dividing all organisms into three major domains of life that includes the prokaryotes that are bacteria but not those that are archaebacteria or archaea compare eubacteria


Pronunciation: \ˌbī-ə-ˈläj-ik\

Function: noun
: a biological product (as a globulin, serum, vaccine, antitoxin, or antigen) used in the prevention or treatment of disease


Pronunciation: \ˈblak-ˌhed\

Function: noun

1: a small plug of sebum blocking the duct of a sebaceous gland esp. on the face compare milium
2: a destructive disease of turkeys and related birds caused by a protozoan of the genus Histomonas (H. meleagridis) that invades the intestinal ceca and liver —called also enterohepatitis, histomoniasis, infectious enterohepatitis


Pronunciation: \ˈbō-ˌtäks\

Function: trademark
used for a preparation of botulinum toxin type A

Chemical Peel

Function: noun
1: a cosmetic procedure for the removal of facial blemishes and wrinkles involving the application of a caustic chemical and esp. an acid (as trichloroacetic acid) to the skin


Pronunciation: \ˈkrän-ik\

Function: adjective

1 a: marked by long duration, by frequent recurrence over a long time, and often by slowly progressing seriousness : not acute <chronic[1] indigestion> <her hallucinations became chronic[1]>
b: suffering from a disease or ailment of long duration or frequent recurrence <a chronic[1] arthritic> <chronic[1] sufferers from asthma>
2 a: having a slow progressive course of indefinite duration used esp. of degenerative invasive diseases, some infections, psychoses, and inflammations <chronic[1] heart disease> <chronic[1] arthritis> <chronic[1] tuberculosis> compare acute 2b(1)
b: infected with a disease-causing agent (as a virus) and remaining infectious over a long period of time but not necessarily expressing symptoms <chronic[1] carriers may remain healthy but still transmit the virus causing hepatitis B>

Coal Tar

coal tar
Pronunciation: \ˈkōl-\

Function: noun
: tar obtained by distillation of bituminous coal and used in the treatment of some skin diseases by direct local application to the skin


Pronunciation: \ˈkäl-ə-jən\

Function: noun
: an insoluble fibrous protein of vertebrates that is the chief constituent of the fibrils of connective tissue (as in skin and tendons) and of the organic substance of bones and yields gelatin and glue on prolonged heating with water


Pronunciation: \ˌkort-i-kō-ˈsti(ə)r-ˌoid also -ˈste(ə)r-\

Function: noun
: any of various adrenal-cortex steroids (as corticosterone, cortisone, and aldosterone) that are divided on the basis of their major biological activity into glucocorticoids and mineralocorticoids


Pronunciation: \ˈsīt-ə-ˌkīn\

Function: noun
: any of a class of immunoregulatory proteins (as interleukin, tumor necrosis factor, and interferon) that are secreted by cells esp. of the immune system


Pronunciation: \ˈdan-drəf\

Function: noun
: scaly white or grayish flakes of dead skin cells esp. of the scalp; also: the condition marked by excessive shedding of such flakes and usu. accompanied by itching


Pronunciation: \ˌdər-mə-ˈbrā-zhən\

Function: noun
: surgical removal of skin blemishes or imperfections (as scars or tattoos) by abrasion (as with sandpaper or wire brushes)


Pronunciation: \ˈdər-məs\

Function: noun
: the sensitive vascular inner mesodermic layer of the skin —called also corium, cutis, cutis vera, derma


Function: noun
pl -mas
also -ma*ta
Pronunciation: \-mət-ə\

: an abnormal excess accumulation of serous fluid in connective tissue or in a serous cavity —called also dropsy


Pronunciation: \ˌer-ə-ˈthē-mə\

Function: noun
: abnormal redness of the skin due to capillary congestion (as in inflammation)


Pronunciation: \ik-ˈsizh-ən\

Function: noun
: surgical removal or resection (as of a diseased part)


Pronunciation: \-ˌəp\

Function: noun
: a sudden increase in the symptoms of a latent or subsiding disease <a flare-up of malaria>


Pronunciation: \ˈfləsh\

Function: noun
: a transitory sensation of extreme heat (as in response to some drugs or in some physiological states) <menopausal flush[1]es>


Pronunciation: \ˈich\

Function: noun

1: an uneasy irritating sensation in the upper surface of the skin usu. held to result from mild stimulation of pain receptors
2: a skin disorder accompanied by an itch; esp: a contagious eruption caused by an itch mite of the genus Sarcoptes (S. scabiei) that burrows in the skin and causes intense itching


Pronunciation: \ˈlā-zər\

Function: noun
: a device that utilizes the natural oscillations of atoms or molecules between energy levels for generating coherent electromagnetic radiation usu. in the ultraviolet, visible, or infrared regions of the spectrum


Pronunciation: \ˈlē-zhən\

Function: noun
: an abnormal change in structure of an organ or part due to injury or disease; esp: one that is circumscribed and well defined


Pronunciation: \lī-ˌken-ə-fə-ˈkā-shən, ˌlī-kən-\

Function: noun
: the process by which skin becomes hardened and leathery or lichenoid usu. as a result of chronic irritation; also: a patch of skin so modified


Pronunciation: \ˈlü-bri-ˌkāt\

Function: transitive verb
: to make smooth, slippery, or oily in motion, action, or appearance <lubricate the eye> <lubricate the skin>


Pronunciation: \ˈmel-ə-nən\

Function: noun
: any of various black, dark brown, reddish brown, or yellow pigments of animal or plant structures (as skin, hair, the choroid, or a raw potato when exposed to air); esp: any of numerous animal pigments that are essentially polymeric derivatives of indole formed by enzymatic modification of tyrosine


Pronunciation: \mə-ˈlan-ə-ˌsīt, ˈmel-ə-nō-\

Function: noun
: an epidermal cell that produces melanin compare melanoblast


Pronunciation: \ˈmen-ə-ˌpoz, ˈmēn-\

Function: noun

1 a (1): the natural cessation of menstruation occurring usu. between the ages of 45 and 55 with a mean in Western cultures of approximately 51
(2): the physiological period in the life of a woman in which such cessation and the accompanying regression of ovarian function occurs —called also climacteric, compare perimenopause
b: cessation of menstruation from other than natural causes (as from surgical removal of the ovaries)
2: see: andropause


Pronunciation: \ˈmī-ˌgrān, Brit often ˈmē-\

Function: noun

1: a condition that is marked by recurrent usu. unilateral severe headache often accompanied by nausea and vomiting and followed by sleep, that tends to occur in more than one member of a family, and that is of uncertain origin though attacks appear to be precipitated by dilatation of intracranial blood vessels
2: an episode or attack of migraine <suffers from migraines> —called also sick headache


Pronunciation: \-ˌdər-mə-ˈtīt-əs\

Function: noun
pl -ti*tis*es
or -tit*i*des
Pronunciation: \-ˈtit-ə-ˌdēz\
: a chronic allergic disorder of the skin characterized by patches of an itching lichenoid eruption and occurring esp. in persons of nervous and emotional instability


Pronunciation: \ˈnäj-(ˌ)ü(ə)l\

Function: noun
: a small mass of rounded or irregular shape: as
a: a small abnormal knobby bodily protuberance (as a tumorous growth or a calcification near an arthritic joint)
b: the nodulus of the cerebellum


Pronunciation: \ˈoint-mənt\

Function: noun
: a salve or unguent for application to the skin; specif: a semisolid medicinal preparation usu. having a base of fatty or greasy material

Ortho Tri-Cyclen

Or*tho Tri–Cy*clen
Pronunciation: \ˌor-thō-ˌtrī-ˈsī-klən\

Function: trademark
used for a preparation of norgestimate and ethinyl estradiol


Pronunciation: \ˈpap-(ˌ)yül\

Function: noun
: a small solid usu. conical elevation of the skin caused by inflammation, accumulated secretion, or hypertrophy of tissue elements


Pronunciation: \-ˈther-ə-pē\

Function: noun
pl -pies
: the application of light for therapeutic purposes


Pronunciation: \ˈpim-pəl\

Function: noun

1: a small inflamed elevation of the skin : see: papule; esp: see: pustule
2: a swelling or protuberance like a pimple


Pronunciation: \ˈpit\

Function: noun
: a hollow or indentation esp. in a surface of an organism: as
a: a natural hollow in the surface of the body
b: one of the indented scars left in the skin by a pustular disease : see: pockmark
c: a usu. developmental imperfection in the enamel of a tooth that takes the form of a small pointed depression


Pronunciation: \ˈpō(ə)r, ˈpo(ə)r\

Function: noun
: a minute opening esp. in an animal or plant; esp: one by which matter passes through a membrane


Pronunciation: \sə-ˈrī-ə-səs\

Function: noun
pl -a*ses
Pronunciation: \-ˌsēz\

: a chronic skin disease characterized by circumscribed red patches covered with white scales

Learn more: What is Psoriasis?
Psoriatic Arthritis

psoriatic arthritis
Function: noun
: a severe form of arthritis accompanied by inflammation, psoriasis of the skin or nails, and a negative test for rheumatoid factor —called also psoriasis arthropathica


Pronunciation: \ˌret-ən-ˈā\

Function: trademark
used for a preparation of tretinoin


Pronunciation: \ˈret-ən-ˌoid\

Function: noun
: any of various synthetic or naturally occurring analogs of vitamin A


Pronunciation: \rō-ˈzā-sh(ē-)ə\

Function: noun
: a chronic inflammatory disorder involving esp. the skin of the nose, forehead, and cheeks that is characterized by congestion, flushing, telangiectasia, and marked nodular swelling of tissues esp. of the nose —called also acne rosacea


Pronunciation: \ˈskā-bēz\

Function: noun
pl scabies
: contagious itch or mange esp. with exudative crusts that is caused by parasitic mites and esp. by a mite of the genus Sarcoptes (S. scabiei)

Sebaceous Gland

sebaceous gland
Function: noun
: any of the small sacculated glands lodged in the substance of the derma, usu. opening into the hair follicles, and secreting an oily or greasy material composed in great part of fat which softens and lubricates the hair and skin

Seborrheic Dermatitis

seborrheic dermatitis
Function: noun
: a red, scaly, itchy dermatitis chiefly affecting areas (as of the face, scalp, or chest) with many large sebaceous glands

Stasis Dermatitis

stasis dermatitis
Function: noun
: inflammation of skin caused by slowing or stoppage of blood flow to the affected area


Pronunciation: \ˈsti(ə)r-ˌoid also ˈste(ə)r-\

Function: noun
: any of numerous natural or synthetic compounds containing a 17-carbon 4-ring system and including the sterols and various hormones and glycosides see anabolic steroid


Function: noun
: a systemic pesticide

T Cell

T cell
Function: noun
: any of several lymphocytes (as a helper T cell) that differentiate in the thymus, possess highly specific cell-surface antigen receptors, and include some that control the initiation or suppression of cell-mediated and humoral immunity (as by the regulation of T and B cell maturation and proliferation) and others that lyse antigen-bearing cells —called also T lymphocyte, see cytotoxic t cell helper t cell suppressor t cell t4 cell


Pronunciation: \ˈtäp-i-kəl\

Function: adjective
: designed for or involving application to or action on the surface of a part of the body <applied a topical anesthetic to numb the skin> <eyedrops used in the topical treatment of glaucoma>


Pronunciation: \-ˌhed\

Function: noun
: see: milium

Audio pronunciation for hear it again
Having trouble hearing a pronunciation?
Click here to listen with your default audio player.
© 2011 Merriam-Webster, Incorporated. Published under license with Merriam-Webster, Inc.

Top Features in Skin, Hair and Nails

15 Ways To Get Better Medicine

People who are actively involved in their medical care stay healthier, recover quicker when they're ill, and live longer, healthier lives.