The estilo desornamentado, is a term used to describe a phase in Spanish architecture during the 16th and early 17th centuries. This style is called estilo desornamentado, or style without ornament because it is just that, a style without all the additional ornamentation. It was developed as a reaction to the Plateresque style which was considered to consist of excessive ornamentation.
The term was first coined in the 19th century, replacing previous terms describing the style which included; Herreran, Escurialense, and Tridentine.
The style began in the 1540's and was at its peak during Juan de Herrera's work(1563-84). One of the most influential buildings categorized as estilo desornamentado, is the Escorial.
Grove Dictionary: estilo desornamentado