U is for Umbrella Tree

• Universe
• U, the chemical symbol for uranium.
• U-turns, ultra, unless, and urgent
• Utah, the only U.S. state that starts with U.
• UV rays, U-Haul, U-Boat
• Ural Mountain Range marks boundary between Europe and Asia.
• Ulna - the long bone of the inner side of the human forearm.
• Umbilical cord
• Ursa Major, the constellation of 7 stars, known as the Big Dipper
• Ukulele, small Hawaiian guitar
• The letter Q can barely function without the letter U.
• The six official languages of the U.N. are:  English, French, Arabic, Chinese, Russian and Spanish. 
• UFO, Uncle Sam, Underground Railway
• U of U  (University of Utah)
• Unique, Utopia, Ultimate, Unanimous, Upbeat, Understanding, Uncluttered