1) Something rubbed out 2) The act of erasing 
• (n.) The act of erasing; a rubbing out; obliteration.
An obsolete term for the scraping away of tissue, especially of bone. ... Origin: L. E-rado, pp. E-rasum, to scrape away ... (05 Mar 2000) ... 
E·ra'sion noun The act of erasing; a rubbing out; obliteration. 
the act of erasing. · · the scraping away of tissue, esp. of bone. · Also calledarthrectomy.excision of a joint.