The term 'Blue Dyes' refers to three different dyes used in the textile industry: Anils (5 letters), Indigos (7 letters), and Woads (5 letters). Anils are synthetic dyes derived from coal tar, while Indigos are natural dyes obtained from plants. Woads are also natural dyes, but they are derived from a flowering plant of the same name. All three of these dyes are used to produce blue hues in fabrics.