Sentence:  Accurate data on the rate of <WSD>corrasion</WSD> would be very helpful in determining whether treatment is an urgent priority. / Overstatement of <WSD>corrasion</WSD> is largely due to the assumption that the height of nails above the timber surface indicatesic the extent of erosion of the wood surface. 
Meaning of the word marked with <WSD> tags:  The wearing away of surface material.