The term "the FTSE Index" is often used interchangeably with "the FTSE 100 Index". Both refer to the top 100 companies listed on the London Stock Exchange, ranked by market capitalization. Another synonym for the FTSE Index is "the Footsie", which is a popular nickname for the index. Other related terms include "FTSE 250 Index", which comprises the next 250 largest companies after the FTSE 100, and "FTSE All-Share Index", which includes all companies listed on the London Stock Exchange. The FTSE Index is widely regarded as a benchmark for the performance of UK stocks and is closely watched by investors and financial analysts.