1. A Program which allows your computer to download and display documents from the World Wide Web. The two most popular browsers are Internet Explorer and Netscape Navigator. It is also a software that allows users to access and navigate the World Wide Web. Some Web browsers, such as Mosaic and Netscape, are graphical. Lynx is a text-based browser. From Glossary of Distance Education and Internet Terminology

2. n. A program specifically designed to help users view and navigate hypertext, on-line documentation, or a database. While this general sense has been present in jargon for a long time, the proliferation of browsers for the World Wide Web after 1992 has made it much more popular and provided a central or default techspeak meaning of the word previously lacking in hacker usage. Nowadays, if someone mentions using a `browser' without qualification, one may assume it is a Web browser. From Jargon Dictionary