plural of keystone

(architecture) The top stone of an arch. / Something on which other things depend for support. / A native or resident of the American state of Pennsylvania.

(transitive) To distort (an image) by projecting it onto a surface at an angle, which for example causes a square to look like a trapezoid.

A census-designated place in Colorado. / A city and town in Iowa. / A ghost town in North Dakota. / A town in South Dakota.

present participle of keystone

simple past tense and past participle of keystone

Having a keystone.

(US, military) A member of the 28th Infantry Division (United States).

plural of Keystoner

(baseball) Second base, because it is often the key to scoring and defense.