Origin: AS. Sund a swimming, akin to E. Swim. See Swim.
5. Founded in truth or right; supported by justice; not to be overthrown on refuted; not fallacious; as, sound argument or reasoning; a sound objection; sound doctrine; sound principles. Hold fast the form of sound words, which thou hast heard of me. (2 Tim. I. 13)
Sound is sometimes used in the formation of self-explaining compounds; as, sound-headed, sound-hearted, sound-timbered, etc. Sound currency, a currency whose actual value is the same as its nominal value; a currency which does not deteriorate or depreciate or fluctuate in comparision with the standard of values.
Origin: OE. Sound, AS. Sund; akin to D. Gezond, G. Gesund, OHG. Gisunt, Dan. & Sw. Sund, and perhaps to L. Sanus. Cf. Sane.
(Science: geography) A narrow passage of water, or a strait between the mainland and an island; also, a strait connecting two seas, or connecting a sea or lake with the ocean; as, the Sound between the Baltic and the german Ocean; long Island Sound. The Sound of Denmark, where ships pay toll. (Camden) Sound dues, tolls formerly imposed by Denmark on vessels passing through the Baltic Sound.
Origin: AS. Sund a narrow sea or strait; akin to Icel, Sw, Dan. & G. Sund, probably so named because it could be swum across. See Swim.
(Science: zoology) A cuttlefish.
2. To ascertain, or try to ascertain, the thoughts, motives, and purposes of (a person); to examine; to try; to test; to probe. I was in jest, And by that offer meant to sound your breast. (Dryden) I've sounded my numidians man by man. (Addison)
Origin: F. Sonder; cf. AS. Sundgyrd a sounding rod, sundline a sounding line (see Sound a narrow passage of water).
Origin: F. Sonde. See Sound to fathom.