V.E.R.A. -- Virtual Entity of Relevant Acronyms (February 2016):

HTTPS
       HyperText Transfer Protocol [SSL] Secured (HTTP, SSL, WWW)


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

HyperText Transmission Protocol, Secure
HTTPS

    (HTTPS) A variant of HTTP used by Netscape for
   handling secure transactions.

   The Netscape Navigator supports a URL access method,
   "https", for connecting to HTTP servers using SSL.

   "https" is a unique protocol that is simply SSL underneath
   HTTP.  You need to use "https://" for HTTP URLs with
   SSL, whereas you continue to use "http://" for HTTP URLs
   without SSL.  The default "https" port number is 443, as
   assigned by the Internet Assigned Numbers Authority.

   (http://netscape.com/info/security-doc.html).

   (1995-01-16)