soundyoudaoicibaDictYouDict
sound: English has no fewer than four distinct words sound. The oldest, ‘channel, strait’ [OE], originally meant ‘swimming’. It came from a prehistoric Germanic *sundam, a derivative of the base *sum-, *swem- ‘swim’ (source of English swim). The sense ‘channel’ was adopted from a related Scandinavian word (such as Danish sund) in the 15th century. Sound ‘undamaged’ [12] is a shortened version of Old English gesund, which went back to prehistoric West Germanic *gasundaz, a word of uncertain origin.

Its modern relatives, German gesund and Dutch gezond ‘well, healthy’, retain the ancestral prefix. Sound ‘noise’ [13] comes via Anglo-Norman soun from Latin sonus ‘sound’, a relative of Sanskrit svan- ‘make a noise’. Amongst the Latin word’s many other contributions to English are consonant, dissonant [15], resonant [16], sonata [17] (via Italian), sonorous [17], and sonnet. Sound ‘plumb the depths’ [14] (as in sounding line) comes via Old French sonder from Vulgar Latin *subundāre, a compound verb formed from Latin sub- ‘under’ and unda ‘wave’ (source of English undulate).
=> swim; consonant, dissonant, resonant, sonata, sonnet, sonorous; surround, undulate
sundryyoudaoicibaDictYouDict
sundry: [OE] Sundry goes back to an Old English syndrig ‘apart, separate’. This, like sunder [OE], is descended ultimately from an Indo-European base *su-, denoting ‘separation’, which also produced Latin sine ‘without’, Welsh hanner ‘half’, and German sondern ‘but’.
sound (v.2)youdaoicibaDictYouDict
"fathom, probe, measure the depth of," mid-14c. (implied in sounding), from Old French sonder, from sonde "sounding line," perhaps from the same Germanic source that yielded Old English sund "water, sea" (see sound (n.2)). Barnhart dismisses the old theory that it is from Latin subundare. Figurative use from 1570s.
sunder (v.)youdaoicibaDictYouDict
Old English sundrian, syndrian "to sunder, separate, divide," from sundor "separately, apart," from Proto-Germanic *sunder (cognates: Old Norse sundr, Old Frisian sunder, Old High German suntar "aside, apart;" German sondern "to separate"), from PIE root *sene- "apart, separated" (cognates: Sanskrit sanutar "far away," Avestan hanare "without," Greek ater "without," Latin sine "without," Old Church Slavonic svene "without," Old Irish sain "different"). Related: Sundered; sundering.