Definition of "root beer"

root beer

/ˈɹut ˌbɪɹ/

noun
countable and uncountable, plural root beers
1. A beverage, most often a carbonated soft drink made from a combination of vanilla, cherry tree bark, licorice root, sarsaparilla root, sassafras root bark, nutmeg, anise, and molasses, among other things.
  Quotations
  In 1919, when Roy Allen and Frank Wright started selling their new root beer beverage to a thirsty America, national Prohibition was taking its grip on the country. Their timing couldn't have been better. No longer able to legally drink real beer, thirsty patriots had to settle for this sweet, foamy conoction derived from roots, herbs, and berries.
  2002, Todd Wilbur, Top Secret Recipes, Penguin
2. (color) A dark reddish-brown color, like the drink.
  Quotations
  I just keep staring at all the ink we have, that wild variety of color, everything from rootbeer, midnight blue and cochineal to mauve, light doe, lilac, south sea green, maize, even pelican black, all line up in these plastic caps […]
  2000, Mark Z. Danielewski, House of Leaves, page 26
  […] most of our bucks have antlers that are varying degrees of brown, from a deep rich root beer shade to walnut to even light amber.
  2006, Tim Lewis, Bows, Swamps, Whitetails, page 28