| Nom | Description |
| Y/C | Y(luminance) Chrominance ( signal ) |
| Y/N | Yes/No |
| Y2K |
| Year 2000 |
| Year Two Thousand |
| YA | Yet Another |
| YAA | Yet Another Acronym |
| YAAS | Yet Another Acronym Server |
| YABA |
| Yet Another Bloody Acronym |
| Yet Another Bloody Acronym slang |
| YABSA | Yet Another Bloody Stupid Acronym |
| YACC | Yet Another Compiler Compiler |
| YADE | Yet Another DSSSL Engine |
| YAFIYGI |
| You Asked For It You Got It |
| You Asked For It, You Got It |
| You asked for it, you got it Usenet, IRC, slang |
| YAG:Nd | Yttrium Aluminum Garnet:Neodym ( LASER ) |
| YAG | Yttrium Aluminum Garnet ( crystal ) |
| YAHOO | Yet Another Hierarchically Officious Oracle |
| YAJSU | Yet Another Java Start Up |
| YAM | Yet Another Modem |
| YAPT | Yet Another Patch Tape |
| YASOS | Yet Another Scheme Object System |
| YAST | Yet Another Setup Tool "Linux, SUSE", "YaST" |
| YAUN | Yet Another Unix Nerd |
| YAY | Yet Another YACC |
| YBCO | Yttrium, Barium, Copper, and Oxygen ( superconducting compound ) |
| YCPS | Yale Center for Parallel Supercomputing |
| YCS | Yamatech Connectivity Solutions |
| YGaIG | Yttrium Gallium Iron Garnet |
| YHBT | You Have Been Trolled |
| YHL | You Have Lost |
| YIG | Yttrium Iron Garnet |
| YIPL | Youth International Party Line |
| YKYBHTLW | You Know You've Been Hacking Too Long When... |
| YMD | Year Month Day |
| YMMV |
| Your Mileage May Vary |
| Your Mileage May Vary slang |
| YMODEM | File transfer protocol |
| YMU | Y-Net Management Unit |
| YOYOW | You Own Your Own Words |
| YP | Yellow Pages |
| YR | Yeah Right |
| YSM | Yourdon Structured Method |
| YST | Yukon Standard Time [ 0900] |
| YTD |
| Year To Date |
| Year-To-Date |
| YTF | YIG - Tuned Filter |
| YUV | (Y)luminance and (U,V)chrominance ( color space standard ) |
