We need your help to fully understand how scientists from different backgrounds define the terms “colluvium” and “alluvium.” We ask that you contribute your perspective by taking the survey at http://goo.gl/forms/fV8RBWKjis. The closing deadline is October 31, 2016. The feedback so far has been positive, and many participants have described the experience as fun. Many commented on how the survey challenged their thinking about these sediments, causing them to more carefully consider potential gaps in their definitions for the terms and their strategies for identifying the materials. Others have expressed great interest in the results because they too have sometimes struggled with how to best use these terms. The following background describes why we are pursuing the question of how scientists are using the terms colluvium and alluvium.