Etymology
Advertisement
contagious (adj.)

late 14c., "contaminating or contaminated, containing contagion" (of air, water, etc.); "communicable" (of disease); also "morally corrupting," from Old French contagieus (Modern French contagieux) and directly from Late Latin contagiosus, from Latin contagio "a touching, contact," often in a bad sense, "a contact with something physically or morally unclean, contagion," from contingere "to touch," from assimilated form of com "with, together" (see con-) + tangere "to touch," from PIE root *tag- "to touch, handle." Figuratively applied to anything apt to spread from one to another (rumor, etc.) from 1650s. Related: Contagiously; contagiousness.

Related entries & more 
Advertisement
yaws (n.)
contagious skin disease, 1670s, from Carib yaya, the native name for it.
Related entries & more 
pink-eye (n.)

contagious eye infection, 1882, American English, from pink (adj.) + eye (n.). Earlier it meant "a small eye" (1570s).

Related entries & more 
rubella (n.)

"German measles," contagious disease characterized by rose-colored eruptions, 1883, Modern Latin, literally "rash," from noun use of neuter plural of Latin rubellus "reddish," diminutive of ruber "red" (from PIE root *reudh- "red, ruddy.").

Related entries & more 
smallpox (n.)
acute, highly contagious disease, 1510s, small pokkes, as distinguished from great pox "syphilis;" from small-pock "pustule caused by smallpox" (mid-15c.); see small (adj.) + pox. Compare French petite vérole. Fatal in a quarter to a third of unvaccinated cases.
Related entries & more 
Advertisement
pestilence (n.)

c. 1300, "any infectious or contagious disease, fatal epidemic," from Old French pestilence "plague, epidemic" (12c.) and directly from Latin pestilentia "a plague, an unwholesome atmosphere," noun of condition from pestilentem (nominative pestilens) "infected, unwholesome, noxious," from pestis "deadly disease, plague" (see pest).

Also in Middle English "wickedness, evil, sin, a vice, that which is morally pestilential."

Related entries & more 
psoriasis (n.)

"chronic non-contagious skin disease characterized by dry, red patches covered with flakes," 1680s, from medical Latin psoriasis, in Late Latin "mange, scurvy," from Greek psōriasis "the itch; a being itchy," from psōrian "to have the itch," from psōra "itch, mange, scab," related to psēn "to rub" (see psilo-). Related: Psoriatic.

Related entries & more 
pestilent (adj.)

late 14c., "contaminated with dangerous disease; deadly, poisonous," from Latin pestilentem (nominative pestilens) "infected, unhealthy," from pestilis "of the nature of a plague," from pestis "deadly contagious disease" (see pest (n.)). Transferred sense of "mischievous, pernicious, hurtful to health or morals" is from 1510s; weakened sense of "troublesome" is from 1590s. Related: Pestilently.

Related entries & more 
pest (n.)

1550s (in imprecations, "a pest upon ____," etc.), "plague, pestilence, epidemic disease," from French peste (1530s), from Latin pestis "deadly contagious disease; a curse, bane," a word of uncertain origin. Meaning "any noxious, destructive, or troublesome person or thing" is attested by c. 1600. Pest-house "hospital for persons suffering from infectious diseases" is from 1610s.

Related entries & more 
mumps (n.)

type of contagious disease characterized by inflammation of the glands, c. 1600, from plural of mump "a grimace" (1590s), originally a verb, "to whine or mutter like a beggar" (1580s), from Dutch mompen "to cheat, deceive," originally probably "to mumble, whine" and of imitative origin (compare mum (interj.), mumble). The infectious disease probably was so called in reference to swelling of the salivary glands of the face and/or to painful difficulty swallowing. Mumps also was used from 17c. to mean "a fit of melancholy, sullenness, silent displeasure."

Related entries & more