"generator for converting mechanical rotation into electric power," 1882, short for dynamo-machine, from German dynamoelektrischemaschine "dynamo-electric machine," coined 1867 by its inventor, German electrical engineer Werner Siemans (1816-1892), from Greek dynamis "power," from dynasthai "to be able, to have power, be strong enough," which is of unknown origin.

"hereditary ruler," 1630s, from Late Latin dynastes, from Greek dynastes "ruler, chief, lord, master" (see dynasty).

"relating to or pertaining to a dynasty," 1800; see dynasty + -ic. Related: Dynastical (1730).

"a race or succession of sovereigns from the same line or family governing a country," mid-15c. (earlier dynastia, late 14c.), from Middle French dynastie and directly from Late Latin dynastia, from Greek dynasteia "power, lordship, sovereignty," from dynastes "ruler, chief," from dynasthai "have power," which is of unknown origin.

in physics, the metric unit of force, 1873, from a specialized scientific use of of Greek dynamis "power" (see dynamic (adj.)); perhaps also influenced by French dyne, which had been proposed c. 1842 as a unit of force in a different sense.

diseased characterized by inflammation of the mucous membrane of the large intestine, late 14c., dissenterie, from Old French disentere (13c.) and directly from Medieval Latin dysenteria, from Greek dysenteria, coined by Hippocrates, from dys- "bad, abnormal, difficult" (see dys-) + entera "intestines, bowels," from PIE *enter "between, among," comparative of root *en "in." Related: Dysenteric.

"failure to function, abnormality or impairment of function," 1914, from dys- "bad, abnormal, difficult" + function (n.). Originally in anatomy and medicine; in sociology by 1949.

"functioning abnormally," 1915, from dysfunction + -al (1). Related: Dysfunctionally.

 "study of the factors producing genetic deterioration, also loosely, "the carrying on of the species by the worst members," 1906, from dys- + ending from eugenics. Hence dysgenic "having or causing a detrimental effect on the race" (1909).

"a difficulty in reading due to a condition of the brain," 1885, from German dyslexie (1883), from Greek dys- "bad, abnormal, difficult" (see dys-) + lexis "word" (taken as "reading"), from legein "speak" (from PIE root *leg- (1) "to collect, gather," with derivatives meaning "to speak (to 'pick out words')") + abstract noun ending -ia. Dyslexic (n.) is recorded by 1946; dyslectic (adj.) by 1962.

Professor Berlin has written a very interesting monograph upon the disease called dyslexia, which he believes allied to the alexia, or word-blindness of Kussmaul. He gives a clinical history of six cases, collected during a period of twenty-three years, all having this peculiarity, that they could read aloud the average type, Jaeger three to five, only a few words in succession. These words were correctly spoken and without confusion or stammering, but as soon as a few words had been read the patients seemed anxious to get rid of the book, and, on being questioned, stated that they had an unpleasant feeling which they could not well define. [The Satellite of the Annual of the Universal Medical Sciences, Philadelphia, November 1887]