Silt. Silt is granular material of a size somewhere between sand and clay whose mineral origin is quartz and feldspar. Silt may occur as a soil or as suspended sediment in a surface water body. It may also exist as soil deposited at the bottom of a water body.
In North America, a grade-separated junction may be referred to as a grade separation or as an interchange â in contrast with an intersection, at-grade, a diamond crossing or a level crossing, which are not grade-separated. 1 Effects.
Definition of grade for English Language Learners. : 1  a level of study that is completed by a student during one year. : 2  the students in the same year of study at a school. : 3  a number or letter that indicates how a student performed in a class or on a test.