Definition - What does .htaccess mean?
The .htaccess file is a configuration file for the Apache HTTP Server that allows administrators to specify options for individual directories. The syntax is exactly the same as Apache's other configuration files. The file is placed in the directories where the web pages are served, to give finer-grained controls than the system-wide configuration file, httpd.conf.
Techopedia explains .htaccess
The .htaccess is a plain text configuration file for the Apache HTTP Server that allows administrators to specify options for directories where web content is served. The initial "." in .htaccess means that the file will be invisible on Unix-like systems in directory listings except with the "ls -a" command. The syntax for the file is exactly the same as the system-wide httpd.conf configuration file. The .htaccess file is placed in the directory where the administrator wants to override Apache's settings.
The Apache Foundation recommends against using .htaccess when a user has access to the system-wide file as using it can slow down the web server.