an intricate knot tied by Gordius, the king of Phrygia, and cut by the sword of Alexander the Great after he heard that whoever undid it would become ruler of Asia
any very difficult problem; insoluble in its own terms
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"
a thin layer covering something; "a second coat of paint"
a heavy fabric suitable for coats
a decorative texture or appearance of a surface (or the substance that gives it that appearance); "the boat had a metallic finish"; "he applied a coat of a clear finish"; "when the finish is too thin it is difficult to apply evenly"
any of various small animals or insects that are pests; e.g. cockroaches or rats; "cereals must be protected from mice and other vermin"; "he examined the child's head for vermin"; "boys in the village have probably been shooting vermin"