Tutoring web design, color is a focus. The tutor mentions analogous colors.
One point of view about color imagines a “color wheel”. The wheel is divided into thirds, one for each of the primary colors red, yellow, and blue. Between the primaries are mixes:
An analogous color set is one that occupies no more than one continuous third of the color wheel. Therefore, pink to orange or purple to teal might be examples of analogous color sets.
Beaird, Jason. The Principles of Beautiful Web Design. SitePoint Pty Ltd, 2010.
Jack of Oracle Tutoring by Jack and Diane, Campbell River, BC.