c. 1400, loscion, "liquid preparation for application to the skin," from Old French lotion (14c.), from Latin lotionem (nominative lotio) "a washing," noun of action from lotus (varied contraction of lavatus), popular form of lautus, past participle of lavere "to wash" (from PIE root *leue- "to wash").
1817, from lotion (n.). There is a nonce-use from 1768. Related: Lotioned; lotioning.
*leuə-, Proto-Indo-European root meaning "to wash."
It forms all or part of: ablution; alluvium; deluge; dilute; elution; lather; latrine; launder; lautitious; lavage; lavation; lavatory; lave; lavish; lotion; lye.
It is the hypothetical source of/evidence for its existence is provided by: Greek louein "to wash, bathe;" Latin lavare "to wash," luere "to wash;" Old Irish loathar "basin," Breton laouer "trough;" Old English leaþor "lather," læg "lye."
"moisten and rub (a bruised or injured part of the body) with a liquid substance," 1610s, from Medieval Latin embrocatus, past participle of embrocare, from Late Latin embrocha, from Greek embrokhe "lotion, fomentation," from embrekhein "to soak in, foment," from assimilated form of en (see en- (2)) + brekhein "to water, wet, rain, send rain," related to brokhe "rain," from PIE root *mergh- "to wet, sprinkle, rain." Related: Embrocated; embrocating; embrocation (early 15c.).
1540s, probably from Old English wice "Applied generally or vaguely to various trees having pliant branches" [OED], from wican "to bend" (from PIE root *weik- (2) "to bend, to wind") + hæsel, used for any bush of the pine family (see hazel (n.)). The North American bush, from which a soothing lotion is made, was so called from 1670s. This is the source of the verb witch in dowsing.
"a wash or lotion for the eyes," 1866, from eye (n.) + wash (n.). Colloquial use for "blarney, humbug" (1884), chiefly British, perhaps is from the notion of "something intended to obscure or conceal facts or true motives." But this, and expression my eye also may be the verbal equivalent of the wink that indicates one doesn't believe what has been said (compare French mon oeil in same sense, accompanied by a knowing pointing of a finger to the eye).