1620s, "bedridden person, one confined to his bed by sickness," from French clinique (17c.), from Latin clinicus "physician that visits patients in their beds," from Greek klinike (techne) "(practice) at the sickbed," from klinikos "of the bed," from kline "bed, couch, that on which one lies," from suffixed form of PIE root *klei- "to lean."
Also "one who defers baptism until the death-bed" (1660s). Sense of "private hospital" is from 1884, from German Klinik in this sense, itself from French clinique, via the notion of "bedside medical education, examination of a patient by an instructor in the presence of students." The modern sense thus reverses the classical one, in which the "clinic" came to the patient. General sense of "conference for group instruction in something" is from 1919.
"one who makes a practical study of disease or sick persons," 1844, from French clinicien, which is formed from Latin clinicus (see clinic) on the model of physicien. Native clinicist is attested from 1860.
1898, from German Heroin, coined 1898 as trademark registered by Friedrich Bayer & Co. for their morphine substitute. According to tradition the word was coined with chemical suffix -ine (2) (German -in) + Greek hērōs "hero" (see hero (n.1)) because of the euphoric feeling the drug provides, but no evidence for this seems to have been found so far.
A new hypnotic, to which the name of 'heroin' has been given, has been tried in the medical clinic of Professor Gerhardt in Berlin. [The Lancet, Dec. 3, 1898]