What is the term for a sauce that is created by boiling a liquid until the water evaporates, thickening the remaining juice?

The term for a sauce created by boiling down a liquid until the water evaporates, thus thickening the remaining juice, is known as a reduction sauce. This technique intensifies the flavors of the liquid by concentrating them as the volume decreases and results in a thicker consistency.

Reduction sauces are often made from stocks, broths, or wine, and they can serve as a flavor base for a variety of dishes. The process of reduction allows for the development of deeper, more complex flavors, making it a favored technique in culinary practices.

The other options do not accurately describe this process. A de-glaze sauce typically refers to a method where liquid is added to a pan in which food has been cooked to dissolve the browned bits left on the pan, while a thickening sauce might imply the addition of a thickening agent such as flour or cornstarch. A condensed sauce is not a standard culinary term associated with the process of reducing a sauce.