The way your shoes slide off your feet when you stumble through your home door after a grueling long run has nothing to do with the term "drop" in running shoes. Instead, the word "drop" in this context refers to the colloquial name for the heel-toe drop, which is a measurement of how much higher a running shoe's heel is than its toe region. The unit of measurement is always millimeters. https://outdoorgearreviews.org/best-zero-drop-trail-running-shoes/