In the accounting world a spreadsheet was and is a large sheet of paper that lays out data and analysis for a businessperson. It spreads or shows all of the costs, income, taxes, etc. on a single sheet of paper for a manager to look at when making a decision. An electronic spreadsheet organizes information into columns and rows. The data can then be "added up" by a formula to give a total or sum. The spreadsheet summarizes information from many sources in one place and presents the information in a format to help a decision maker see the financial "big picture" for the company. A program that has a collection of cells whose values can be displayed on a computer screen. By changing cell definitions and having all cell values reevaluated, a user can readily observe the effects of those changes. Decision support systems built using spreadsheet software are sometimes called Spreadsheet-based DSS.
from See "A Brief History of Spreadsheets" by Daniel Power at URL http://dssresources.com/history/sshistory.html.