The crossword solution for the term 'Trendy Smoothie Seed' is CHIA, which is a four-letter word. CHIA seeds are a popular ingredient in smoothies due to their high nutritional content and health benefits. They are a good source of fiber, protein, and omega-3 fatty acids, and are also rich in antioxidants. CHIA seeds have become increasingly trendy in recent years as more people look for healthier alternatives to traditional smoothie ingredients.