1. [adjective] Having red as its color.
2. [adjective] Of hair, having an orange-brown colour; ginger.
3. [adjective] (often capitalized) Leftwing, socialist, or communist.
4. [adjective] (US) (modern) Supportive of or dominated by the political party represented by the color red, especially the U.S. Republican Party.
5. [adjective] (US) (modern) Of, pertaining to, or run by (a member of) the political party represented by the color red, especially the U.S. Republican Party.
6. [adjective] (British) Supportive of the Labour Party.
7. [adjective] (Germany) (politics) Related to the Social Democratic Party.
8. [adjective] (astronomy) Of the lower-frequency region of the (typically visible) part of the electromagnetic spectrum which is relevant in the specific observation.
9. [adjective] (particle physics) Having a color charge of red.
10. [noun] (countable and uncountable) Any of a range of colours having the longest wavelengths, 670 nm, of the visible spectrum; a primary additive colour for transmitted light: the colour obtained by subtracting green and blue from white light using magenta and yellow filters; the colour of blood, ripe strawberries, etc.
11. [noun] (countable) A revolutionary socialist or (most commonly) a Communist; (usually capitalized) a Bolshevik, a supporter of the Bolsheviks in the Russian Civil War.
12. [noun] (countable) (snooker) One of the 15 red balls used in snooker, distinguished from the colours.
13. [noun] (countable and uncountable) Red wine.
14. [noun] (slang) The drug secobarbital; a capsule of this drug.
15. [noun] (informal) A red light (a traffic signal)
16. [noun] (Ireland) (UK) (beverages) (informal) red lemonade
17. [noun] (particle physics) One of the three color charges for quarks.
18. [verb] (archaic) simple past tense and past participle of rede
19. [verb] (colloquial) Alternative spelling of redd
20. [verb] (transitive) (Pennsylvania) Alternative spelling of redd
21. [noun] A Communist
22. [noun] A supporter of a sports team who wears red as part of their kit.
23. [adjective] Communist
24. [noun] (acronym) Reverse electrodialysis.
