means Vibrations traveling through air or other matter that you can hear; or, as an adjective, something solid, healthy, and trustworthy.

from The noise sense comes from Old French 'son' and Latin 'sonus,' meaning a noise or tone — a cousin of 'sonic' and 'resonate.' The 'healthy, solid' sense is a different word entirely, from Old English 'gesund,' related to German 'gesund' (the 'gesundheit' you sneeze toward). Two unrelated families that drifted into the same spelling. The 'sound the depths' meaning — to measure water — is yet a third, likely from Old French 'sonder,' possibly tied to a root for 'sea.' Three words wearing one coat.