2、来自古法语 son,声音，来自拉丁语 sonus,声音，来自 PIE*swen,发声，词源同 sonic,consonant. 引申诸相关词义。插入字母 d.
4、来自中古英语 sound,来自古英语 sund,完整的，健康的，来自 Proto-Germanic*sundaz,健康的， 来自 PIE*swent,*swen,健康的，词源同 sane,gesundheit.引申诸相关词义。
6、来自古英语 sund,海峡，海湾，狭窄水域，游泳能穿过的水域，来自 Proto-Germanic*sunda, 游泳，来自 PIE*swem,游泳，词源同 swim.字母 m,n 音变，比较 simple,single.
8、词源不确定，可能来自 subundare,测水深，来自 sub-,在下，unda,水，词源同 undulate,water. 或来自 sound,声音，发声，听起来。引申比喻义试探，调查。
2、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’  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’  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 , resonant , sonata  (via Italian), sonorous , and sonnet. Sound ‘plumb the depths’  (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
4、"noise, what is heard, sensation produced through the ear,"late 13c., soun, from Old French son"sound, musical note, voice,"from Latin sonus"sound, a noise,"from PIE *swon-o-, from root *swen-"to sound"(cognates: Sanskrit svanati"it sounds,"svanah"sound, tone;"Latin sonare"to sound;"Old Irish senim"the playing of an instrument;"Old English geswin"music, song,"swinsian"to sing;"Old Norse svanr, Old English swan"swan,"properly"the sounding bird"). The terminal -d was established c. 1350-1550 as part of a tendency to add -d- after -n-. First record of sound barrier is from 1939. Sound check is from 1977; sound effects is 1909, originally live accompaniments to silent films. The experts of Victor ... will ... arrange for the synchronized orchestration and sound effects for this picture, in which airplane battles will have an important part. ["Exhibitor's Herald & Moving Picture World,"April 28, 1928]
6、"free from special defect or injury,"c. 1200, from Old English gesund"sound, safe, having the organs and faculties complete and in perfect action,"from Proto-Germanic *sunda-, from Germanic root *swen-to-"healthy, strong"(cognates: Old Saxon gisund, Old Frisian sund, Dutch gezond, Old High German gisunt, German gesund"healthy,"as in the post-sneezing interjection gesundheit; also Old English swið"strong,"Gothic swinþs"strong,"German geschwind"fast, quick"), with connections in Indo-Iranian and Balto-Slavic. Meaning"right, correct, free from error"is from mid-15c. Meaning"financially solid or safe"is attested from c. 1600; of sleep,"undisturbed,"from 1540s. Sense of"holding accepted opinions"is from 1520s.
8、"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.
10、"narrow channel of water,"c. 1300, from Old Norse sund"a strait, swimming,"or from cognate Old English sund"act of swimming, stretch of water one can swim across, a strait of the sea,"both from Proto-Germanic *sundam-, from *swum-to-, suffixed form of Germanic root *swem-"to move, stir, swim"(see swim (v.)).
12、early 13c., sounen"to be audible, produce vibrations affecting the ear,"from Old French soner (Modern French sonner) and directly from Latin sonare"to sound"(see sonata). From late 14c. as"cause something (an instrument, etc.) to produce sound."Related: Sounded; sounding.