redness

Concise Oxford English Dictionary © 2008 Oxford University Press:
red/red/

▶adjective (redder, reddest)

• 1 of a colour at the end of the spectrum next to orange and opposite violet, as of blood or rubies.

  ■ (of hair or fur) of a reddish-brown colour.

  ■ (of a person's face) red due to embarrassment, anger, or heat.

  ■ dated or offensive (of a people) having reddish skin.

• 2 (of wine) made from dark grapes and coloured by their skins.

• 3 of or denoting the suits hearts and diamonds in a pack of cards.

• 4 denoting a red light or flag used as a signal to stop.

  ■ denoting something forbidden, dangerous, or urgent.

• 5 (of a ski run) of the second-highest level of difficulty.

• 6 informal, chiefly derogatory communist or socialist.

• 7 archaic or literary involving bloodshed or violence.

▶noun

• 1 red colour or pigment.

• 2 informal, chiefly derogatory a communist or socialist.

• 3 (the red) the situation of having spent more than is in one's bank account.

– phrases
the red planet Mars.
see red informal become very angry suddenly.

– derivatives
reddish adjective,
reddy adjective,
redly adverb,
redness noun.

– origin OE rēad, of Gmc origin.