Weathering is the process that breaks down earth's crust into smaller sediments.
Erosion is the process of transporting sediments to a different location. Sediments get eroded by wind, water, ice and gravity. Wind has its own force. There is more erosion if the sediment is windward, the same direction from which wind if coming. There is less erosion if the sediment is leeward, sheltered from prevailing winds by landscape. Gravity is a driving force that causes streams and ice to move. Water is the most common form of erosion. Streams and tributaries (smaller streams that flow into larger streams) move sediments further distances, and stream velocity causes sediments of the same size to move together. Mass wasting at a watershed, the area of land drained by one stream, is caused by gravity pulling sediments downhill.
Deposition is when sediments settle in a new location. Depending upon the amount of energy present, sediments can be sorted -- such as graded bedding, beaches, sand dunes -- or unsorted sediments -- such as glacial deposits and mass wasting.
Mass wasting, also known as slope movement or mass movement, is the process by which soil, rock and other materials move downslope under the force of gravity. Types of mass wasting include creep, slides, flows, topples, and falls, each with its own characteristic features, and taking place over timescales from seconds to years. Mass wasting occurs on both terrestrial and submarine slopes.
If you are unfamiliar with the topic of mass wasting, this website, provided by Professor Chuck DeMats at the Department of Geoscience, University of Wisconsin-Madison, is a great resource.