Case - the enclosing frame all around a door or window opening; "the casings had rotted away and had to get replaced" portfolio - a substantial, flat, slender case for carrying loose papers or drawings or maps; usually leather-based; "he remembered her mainly because she was carrying a sizable portfolio" https://hbrcasestudyanalysis10936.bloguetechno.com/a-review-of-harvard-case-study-analysis-71574051