"chemical decomposition by water," 1879, formed in English from hydro- + Greek lysis "a loosening, a dissolution," from lyein "to loosen, dissolve" (from PIE root *leu- "to loosen, divide, cut apart"). Related: Hydrolitic (1875).
before vowels hydr-, word-forming element in compounds of Greek origin, meaning "water," from Greek hydro-, combining form of hydor "water" (from suffixed form of PIE root *wed- (1) "water; wet"). Also sometimes a combining form of hydrogen.
It is the hypothetical source of/evidence for its existence is provided by: Sanskrit lunati "cuts, cuts off," lavitram "sickle;" Greek lyein "to loosen, untie, slacken," lysus "a loosening;" Latin luere "to loose, release, atone for, expiate;" Old Norse lauss "loose, free, unencumbered; vacant; dissolute;" Old English losian "be lost, perish."
in reference to a crystalline organic compound, 1934, from the -lys- in hydrolysis (thus from Greek lysis "a loosening, a dissolution," from lyein "to loosen, dissolve;" from PIE root *leu- "to loosen, divide, cut apart") + the first syllable of ergot (a fungus from which the chemical was first obtained) + -ic.
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Definitions of hydrolysis from WordNet
a chemical reaction in which water reacts with a compound to produce other compounds; involves the splitting of a bond and the addition of the hydrogen cation and the hydroxide anion from the water;