Donning means to put on and use PPE properly to achieve the intended protection and minimize the risk of exposure. Doffing means removing PPE in a way that avoids self-contamination. For example, avoid skin and mucous membrane contact with potentially infectious materials, and chemical and biological agents. More @Wikipedia
Hover over any link to get a description of the article. Please note that search keywords are sometimes hidden within the full article and don't appear in the description or title.