What is "sour dock"

Sour \Sour\, a. [Compar. Sourer; superl. Sourest.] [OE. sour, sur, AS. s?r; akin to D. zuur, G. sauer, OHG. s?r, Icel. s?rr, Sw. sur, Dan. suur, Lith. suras salt, Russ. surovui harsh, rough. Cf. Sorrel, the plant.]

1. Having an acid or sharp, biting taste, like vinegar, and the juices of most unripe fruits; acid; tart.

   All sour things, as vinegar, provoke appetite.
   --Bacon.

2. Changed, as by keeping, so as to be acid, rancid, or musty, turned.

3. Disagreeable; unpleasant; hence; cross; crabbed; peevish; morose; as, a man of a sour temper; a sour reply. ``A sour countenance.''
   --Swift.

   He was a scholar . . . Lofty and sour to them that loved him not, But to those men that sought him sweet as summer.
   --Shak.

4. Afflictive; painful. ``Sour adversity.''
   --Shak.

5. Cold and unproductive; as, sour land; a sour marsh.

   Sour dock (Bot.), sorrel.

   Sour gourd (Bot.), the gourdlike fruit Adansonia Gregorii, and A. digitata; also, either of the trees bearing this fruit. See Adansonia.

   Sour grapes. See under Grape.

   Sour gum (Bot.) See Turelo.

   Sour plum (Bot.), the edible acid fruit of an Australian tree ( Owenia venosa); also, the tree itself, which furnished a hard reddish wood used by wheelwrights.

   Syn: Acid; sharp; tart; acetous; acetose; harsh; acrimonious; crabbed; currish; peevish.

n. European sorrel with large slightly acidic sagittate leaves grown throughout north temperate zone for salad and spring greens [syn: garden sorrel, Rumex acetosa]