1550s, "to strike," from French percussir, from Latin percussus, past participle of percutere "to strike hard, beat" (see percussion). Especially, in medicine, "to tap or strike for diagnostic purposes" (1821, implied in percussed). Related: Percussing.
late 14c., epatike, from Old French hepatique or directly from Latin hepaticus "pertaining to the liver," from Greek hēpatikos, from hēpar (genitive hēpatos) "liver" (see hepatitis). As a noun, "medicine for the liver," from late 15c.
"assuaging, palliating," early 15c., from Medieval Latin lenitivus, from Latin lenitus, past participle of lenire "to soften, alleviate, pacify" (from PIE root *lē- "to let go, slacken"). As a noun, "a lenitive medicine," from early 15c.
late 14c., "bile," as one of the humors, an excess of which was supposed in old medicine to cause irascibility or temper, from Old French colere "bile, anger," from Late Latin cholera "bile" (see cholera).
mid-15c., "a falling back into error or wrongdoing, moral backsliding," from relapse (v.) or else from Medieval Latin relapsus. In medicine, "a falling back into a disease or symptom during or after convalescence," from 1580s.
in medicine, "a drug which promotes or facilitates phlegm or other such matter from the body by means of expectoration," 1782, from Latin expectorantem (nominative expectorans), present participle of expectorare (see expectorate). From 1811 as an adjective.