The term '2018 Spring Summer Fashion Runway Adjacent Colors' refers to the color trends showcased in fashion runways during the 2018 spring and summer seasons. Adjacent colors in fashion are those that are next to each other on the color wheel, such as red and orange, or blue and purple. Designers often use these colors to create harmonious and complementary outfits. The 2018 trends may include specific color combinations that were popular during that season, influencing fashion designers, retailers, and consumers.