Definition of "flagstaff"

Snowball had found in the harness-room an old green tablecloth of Mrs. Jones's and had painted on it a hoof and a horn in white. This was run up the flagstaff in the farmhouse garden every Sunday morning.

1945, George Orwell, chapter 3, in Animal Farm‎

The abolition of the death penalty has been the flagstaff of the permissive society. We know what that has meant for the people of this country. Local newspapers are full of articles about robbery, murder, rape and, literally, pillage.

1988, Rhodes Boyson, Hansard, 7 June, 1988, Criminal Justice Bill