A sour or acid substance; whatever produces a painful effect.

1. To cause to become sour; to cause to turn from sweet to sour; as, exposure to the air sours many substances. "So the sun's heat, with different powers, Ripens the grape, the liquor sours." (Swift)

2. To make cold and unproductive, as soil.

3. To make unhappy, uneasy, or less agreeable. "To sour your happiness I must report, The queen is dead." (Shak)

4. To cause or permit to become harsh or unkindly. "Souring his cheeks." "Pride had not sour'd nor wrath debased my heart." (Harte)

5. To macerate, and render fit for plaster or mortar; as, to sour lime for business purposes.

Origin: AS. Srian to sour, to become sour.

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." "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."

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

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

Synonyms: Acid, sharp, tart, acetous, acetose, harsh, acrimonious, crabbed, currish, peevish.

Origin: OE. Sour, sur, AS. Sr; akin to D. Zuur, G. Sauer, OHG. Sr, Icel. Srr, Sw. Sur, Dan. Suur, Lith. Suras salt, Russ. Surovui harsh, rough. Cf. Sorrel, the plant.

(01 Mar 1998)