A Search Engine is a "program that searches documents for specified keywords and returns a list of the documents where the keywords were found." (Webopedia)
Some of the more popular search engines are:
-Google
-Yahoo
-Bing
-AltaVista
-Ask
A useful search engine for academic resources is Google Scholar.
A Web Browser is "a software application used to locate and display Web pages. " (Webopedia)
Some of the more popular web browsers are:
-Internet Explorer
-Firefox
-Chrome
-Opera