Definition (Geography): 

Abrasion is the process of wearing away or eroding the surface of rocks, soil, or other landforms due to the scraping or rubbing action of natural forces like wind, water, or ice.

Explanation: 

In geography, abrasion is a type of erosion where materials like rocks or sediment are worn down by being scraped or rubbed against each other or against a surface. For example, when a river carries rocks and they collide with each other or the riverbed, they get smoothed out or reduced in size. Similarly, wind carrying sand particles can scrape against rocks, shaping or eroding them over time. This process plays a key role in shaping landscapes.

Example: 

When a river flows and the rocks in it rub against each other, they become smooth and rounded over time, like pebbles on a riverbank. This smoothing process is an example of abrasion.