summing up an abbreviation is a shortening of a word or a phrase an acronym is an abbreviation that forms a word an initialism is an abbreviation that uses the first letter of each word in the phrase thus some but not all initialisms are acronyms
ROI, or return on investment, is a common business term used to identify past and potential financial returns. Managers and executives look to the ROI of a project or endeavor because this indicates how successful a venture will be.
(A return on investment is the money a person earns from their investment, for instance a share of stock purchased for $100 dollars and sold for $200 offers a 100% ($100) ROI.) The ROI you use can be the one you expect from the business or one from another investment you may pursue in lieu of the business.