noun

• (figurative) Anything that provides similar protection.
  "The fighters provide a defensive air umbrella over the battle group."
• (figurative) Anything that provides similar overarching coverage of a range of concepts, purposes, groups, etc.
  "The test facility was established under the umbrella of the company's quality program."
• (ice hockey) A strategy in which five players in the offensive zone form an umbrella-shaped formation around the opposition's goal net.
• (photography, television) An umbrella-shaped reflector with a white or silvery inner surface, used to diffuse a nearby light.
  "Using umbrellas for shooting a wedding party is ok, but not necessary."

verb

• (transitive) To cover or protect, as if by an umbrella.
  "Experts with saws and ladders came and lopped off the lower branches. This sent the tree's growth rushing violently to her head in a lush overhanging which umbrellaed the House of All Sorts."
• (intransitive) To form the dome shape of an open umbrella.
  "Bright yellow gowns fit them tightly and umbrellaed from their waist to just below the knees."
• (intransitive) To move like a jellyfish.
  "The light catches the filigreed tendrils and graceful motion of the jellies, their orange bodies umbrella-ing along like fairy parasols come to life."