The term 'Big Name in Spreadsheets' can be summarized by the crossword solution EXCEL, which is a five-letter word. EXCEL is a spreadsheet program developed by Microsoft and is one of the most popular programs of its kind. It is used by businesses, schools, and individuals for data analysis, calculations, and other tasks. EXCEL is known for its powerful features and ease of use, making it a big name in the world of spreadsheets.