RECOMMENDED LESSONS: Runoff Runoff is precipitation that did not get (infiltrated) absorbed into the soil, or did not evaporate, and therefore made its way from the ground surface into places that water collect. Runoff causes erosion, and also carry chemicals and substances on the ground surface along to the rivers where the water ends up.
Noun. 1. obelisk-a stone pillar having a rectangular cross section tapering towards a pyramidal top. pillar, column-a vertical cylindrical structure standing alone and not supporting anything (such as a monument).
The Washington Monument is a structure called an obelisk, measuring 555 feet and 5 1/8 inches high. According to Wikipedia, an obelisk is: âA tall, four-sided, narrow tapering monument which ends in a pyramid-like shape at the top.