Why do we say we "drop" perpendicular lines

I often see problems or hear people talk about problems where they say that one "drops" a perpendicular line. This YouTube video at 9:30 https://www.youtube.com/watch?v=GKYBX3KM7CY specifically prompted me to ask this question because he says "so I’m going to drop the perpendicular down" and it hit me that this idea of "dropping" perpendicular lines comes up everywhere. A quick google search for more examples of people writing that you drop perpendicular lines gives lots of examples.

I’m just curious if anyone has an idea for where the idea of "dropping" perpendicular lines came from, or why we use it for perpendicular lines and not other lines, etc.