What does .SGML stand for?

What does .SGML mean?

SGML	Standard Generalized Markup Language Academic & Science » Electronics
SGML	Standard Generalized Markup Language Internet
SGML	Standard Generalized Markup Language Governmental » Military
SGML	Standard Generalized Markup Language Computing » General
.SGML	text/sgml Internet » MIME Types
SGML	Standard Generalized Markup Language document Computing » File Extensions
SGML	Sounds Great Maybe Later Miscellaneous » Unclassified
SGML	The Standard Generalized Markup Langua Miscellaneous » Unclassified
SGML	Standardised General Markup Language Miscellaneous » Unclassified