Wiktionary:Word of the day/December 24

1. An evergreen tree (usually a conifer), or an artificial tree made to resemble this, which is typically decorated with lights and ornaments and often an angel or star at its tip, and used as a decoration during the Christmas holiday season.
2. (by extension) Something which resembles a Christmas tree (sense 1) in appearance (for example, in having coloured lights) or shape.
   1. (informal) Something which is elaborately decorated.
   2. (bodybuilding) A pattern of muscles visible in the lower back, resembling in outline the shape of a conifer.
   3. (chiefly military)
      1. (aviation, nautical, slang) A panel of indicator lights in an aircraft or a submarine.
      2. (US, aviation, historical) An alert area at an air base with aircraft parked in stubs arranged at a 45-degree angle to a central taxiway to enable them to move rapidly to a runway; these were constructed by the Strategic Air Command of the United States Air Force during the Cold War (generally 1947–1991).
   4. (motor racing) A pole with lights, similar to a traffic signal, used for signalling the start of an automobile race.
   5. (oil industry, slang) A collection of gauges, valves, and other components installed at the top of wellhead to control the flow of gas or oil.
3. (by extension) A Christmas party, especially one organized for (underprivileged) children by a charity, a school, etc.
4. (Australia) Often with a descriptive word: any of several shrubs or trees native to Australia which bloom in summer at the end of the year around Christmastime, and so may be used as a Christmas decoration; especially the fire tree or moodjar (Nuytsia floribunda).
5. (New Zealand) Synonym of pohutukawa (“a coastal evergreen tree, Metrosideros excelsa, native to New Zealand and producing a brilliant display of red flowers with prominent stamens around Christmastime”)

Have yourself a merry little Christmas Eve!