UMBRELLA

• um‧brel‧la [countable]
• 1 an object that you use to protect yourself against rain or hot sun. It consists of a circular folding frame covered in cloth [↪ parasol]:
• It started to rain, so Tricia stopped to put upher umbrella.
• I spent the day on the beach, lying under a beach umbrella, reading.
• 2

   umbrella organization/group/agency etc

  an organization that includes many smaller groups
• 3

   umbrella term/word/title etc

  a word whose meaning includes many different types of a particular thing:
• District nurses, health visitors, and school nurses will come under the umbrella term 'community nursing'.
• 4

   (come/work etc) under the umbrella of something

  to be part of a larger organization or involved in the work done by it:
• The international education program came under the umbrella of the State Department.
• 5 the protection given by a powerful country, army, a weapons system etc:
• the American nuclear umbrella over western Europe

Definition from the Longman Dictionary of Contemporary English
Advanced Learner's Dictionary.