The Jargon File (version 4.4.7, 29 Dec 2003):

dot file
 n.

    A file that is not visible by default to normal directory-browsing tools
    (on Unix, files named with a leading dot are, by convention, not normally
    presented in directory listings). Many programs define one or more dot
    files in which startup or configuration information may be optionally
    recorded; a user can customize the program's behavior by creating the
    appropriate file in the current or home directory. (Therefore, dot files
    tend to creep ? with every nontrivial application program defining at
    least one, a user's home directory can be filled with scores of dot files,
    of course without the user's really being aware of it.) See also profile
    (sense 1), rc file.


The Free On-line Dictionary of Computing (30 December 2018):

dot file

    A Unix application program
   configuration file.  On Unix, files named with a leading dot
   are not normally shown in directory listings.  Many programs
   define one or more dot files in which startup or configuration
   information may be optionally recorded; a user can customise
   the program's behaviour by creating the appropriate file in
   the current or home directory.

   Dot files tend to proliferate - with every nontrivial
   application program defining at least one, a user's home
   directory can be filled with scores of dot files, without the
   user really being aware of it.  Common examples are .profile,
   .cshrc, .login, .emacs, .mailrc, .forward, .newsrc, .plan,
   .rhosts, .sig, .xsession.

   See also profile, rc file.

   [Jargon File]

   (1994-12-07)