Ten years after the author first wrote in "Montessori Life" about the challenges of identifying, diagnosing, and treating sensory processing disorder (SPD) in young children many of the same difficulties remain. The good news is that more people know about sensory integration (SI) and SPD than ever before. The bad news? Little has been done to integrate the information that has been learned into most children's early lives. During this decade, most American schools have become less sensory friendly. Opportunities for outdoor time and active play have dramatically decreased, both at home and school. Children spend more time in front of screens and less time experiencing the world through a variety of senses. More children are being diagnosed with a range of disorders and often placed on medications that may or may not help. As high-stakes testing has become firmly ingrained, children are allowed to move less and personalize their learning experiences less, though it is known that developmentally they need both of those more. Though Montessorians counter this trend, their voices must be used to make developmentally appropriate, sensory supportive learning environments available to "every child," not just those in their own classrooms. To do so, there must be a common understanding of the issue at hand. In this article, the author defines some terminology related to sensory integration.