Apache HTTP Server is a freely-available Web server software package that is distributed under an open source license. Apache HTTP server was formerly known as Apache Web Server and has been offered since 1995 through the Apache Software Foundation.
The software offers an extensible and secure web server with services in sync with modern HTTP standards. HTTP Server is compatible with most UNIX-based operating systems (such as Mac OS, Linux, Solaris, Digital UNIX, and AIX), on other UNIX/POSIX-derived systems and on Microsoft Windows.
Apache HTTP Server was the most popular webserver from 1996 until June of 2016.While Apache still remains one of the world’s most heavily-used webservers it lost market share to NGINX, Microsoft and others since 2016.
According to the Apache Software Foundation:
The name 'Apache' was chosen from respect for the Native American Indian tribe of Apache, well-known for their superior skills in warfare strategy and their inexhaustible endurance. It also makes a cute pun on "a patchy web server" -- a server made from a series of patches -- but this was not its origin. The group of developers who released this new software soon started to call themselves the "Apache Group.”