The common rudd (Scardinius erythrophthalmus), a freshwater fish. / Any of various grass-skippers or hesperiid butterflies of the genus Matapa.

(intransitive, aviation, travel, colloquial) Often followed by it: to travel on a red-eye (“an overnight airplane flight”).

Particularly significant or positive.

Ostentatiously special; VIP

Parachute Regiment / Manchester United F.C. / Belgium national football team

(transitive, sports) To show (a player) a red card, and dismiss them from the playing area; to send off.

A tree in the genus Alnus; Alnus rubra. / A South African tree Cunonia capensis

(cytology) An erythrocyte (red blood cell).

(Internet, Wiktionary and WMF jargon) A red hyperlink that directs to a nonexistent page of a wiki.

(American football) The area extending twenty yards from the end zone, where a team in possession of the ball is expected to score.