What is "sound currency"

Sound \Sound\, a. [Compar. Sounder; superl. Soundest.] [OE. sound, AS. sund; akin to D. gezond, G. gesund, OHG. gisunt, Dan. & Sw. sund, and perhaps to L. sanus. Cf. Sane.]

1. Whole; unbroken; unharmed; free from flaw, defect, or decay; perfect of the kind; as, sound timber; sound fruit; a sound tooth; a sound ship.

2. Healthy; not diseased; not being in a morbid state; -- said of body or mind; as, a sound body; a sound constitution; a sound understanding.

3. Firm; strong; safe.

   The brasswork here, how rich it is in beams, And how, besides, it makes the whole house sound.
   --Chapman.

4. Free from error; correct; right; honest; true; faithful; orthodox; -- said of persons; as, a sound lawyer; a sound thinker.

   Do not I know you a favorer Of this new seat? Ye are nor sound.
   --Shak.

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.

6. heavy; laid on with force; as, a sound beating.

7. Undisturbed; deep; profound; as, sound sleep.

8. Founded in law; legal; valid; not defective; as, a sound title to land.

   Note: Sound is sometimes used in the formation of self-explaining compounds; as, sound-headed, sound-hearted, sound-timbered, etc.

   Sound currency (Com.), 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.