having the function of uniting a group of similar things; "the Democratic Party is an umbrella for many liberal groups"; "under the umbrella of capitalism"
a formation of military planes maintained over ground operations or targets; "an air umbrella over England"
a lightweight handheld collapsible canopy
covering or applying simultaneously to a number of similar items or elements or groups; "an umbrella organization"; "umbrella insurance coverage"
any of numerous small rodents typically resembling diminutive rats having pointed snouts and small ears on elongated bodies with slender usually hairless tails
a hand-operated electronic device that controls the coordinates of a cursor on your computer screen as you move it around on a pad; on the bottom of the device is a ball that rolls on the surface of the pad; "a mouse takes much more room than a trackball"
a book (or manuscript) consisting of large sheets of paper folded in the middle to make two leaves or four pages; "the first folio of Shakespeare's plays"
a precautionary measure warding off impending danger or damage or injury etc.; "he put an ice pack on the injury as a precaution"; "an insurance policy is a good safeguard"; "we let our guard down"
a person who contributes to the fulfillment of a need or furtherance of an effort or purpose; "my invaluable assistant"; "they hired additional help to finish the work"