Entries linking to sourness
Old English sur "sour, tart, acid, fermented," from Proto-Germanic *sura- "sour" (source also of Old Norse surr, Middle Dutch suur, Dutch zuur, Old High German sur, German sauer), from PIE root *suro- "sour, salty, bitter" (source also of Old Church Slavonic syru, Russian syroi "moist, raw;" Lithuanian sūras "salty," sūris "cheese").
Meaning "having a peevish disposition" is from early 13c. Sense in whisky sour (1885) is "with lemon added" (1862). Sour cream is attested from 1855. French sur "sour, tart" (12c.) is a Germanic loan-word.
word-forming element denoting action, quality, or state, attached to an adjective or past participle to form an abstract noun, from Old English -nes(s), from Proto-Germanic *in-assu- (cognates: Old Saxon -nissi, Middle Dutch -nisse, Dutch -nis, Old High German -nissa, German -nis, Gothic -inassus), from *-in-, originally belonging to the noun stem, + *-assu-, abstract noun suffix, probably from the same root as Latin -tudo (see -tude).
