Indigo dye is the color that is called Añil (the Spanish word for "indigo dye") in the Guía de coloraciones (Guide to colorations) by Rosa Gallego and Juan Carlos Sanz, a color dictionary published in 2005 that is widely popular in the Hispanophone realm. Indigo dye is the basis for all the historical navy blue colors, since in the 18th, 19th, and early 20th century, almost all navy uniforms were made by dyeing them with various shades of indigo dye.