Y2K - Year 2000
YAAS - Yet Another Acronym Server
YACC - Yet Another Compiler Compiler
YADE - Yet Another DSSSL Engine
YAG - Yttrium-Aluminium-Garnet
YAHOO - Yet Another Hierarchical Officious Oracle
YAMD - Yet Another Malloc Debugger
YAPC - Yet Another Perl Conference
YASOS - Yet Another Scheme Object System
YaST - Yet another Setup Tool
YAUN - Yet Another UNIX Nerd
YaWPS - Yet another Web Portal System
YAY - Yet Another YACC
YBCO - Yttrium and Barium in Copper Oxide
YCMB - Yellow, Cyan, Magenta and Black
YCPS - Yale Center for Parallel Supercomputing
YDI - Young Design, Inc.
YDL - Yellow Dog Linux
YES - Yahoo! Enterprise Solutions
YOU - YaST Online Update
YSM - Yourdon Structured Method