Definition of "rotunda"

(architecture) A round building, usually small, often with a dome.  examples

(typography, frequently capitalized) A Gothic typeface used in early printed books in Northern Italy, based on a rounded script developed in the 13th cent.; the manuscript hand on which this typeface was based.  examples

(Philippines) A roundabout; a road junction at which traffic streams circularly around a central island.  examples

(geometry) A form of cupola that has pentagons rather than squares or rectangles.  examples