FIELD COVER is a term used to describe the covering of an outdoor area with either a tarp (4 letters) or SOD (3 letters). Tarp is a waterproof material that is used to cover fields and protect them from the elements. SOD is a layer of grass and soil that is used to cover fields and provide a natural, green look. Both tarp and SOD are used to protect fields from the weather and keep them in good condition.