| Acronym | Definition |
|---|
| Y | Year |
| Y | Yes |
| Y | YMCA or YWCA (Young Men's Christian Association or Young Women's Christian Association) |
| Y | Why? |
| Y | Yahoo! (Internet search engine) |
| Y | Yellow |
| Y | Corporation (IRB) |
| Y | Income (economics) |
| Y | Economy (class airfare) |
| Y | Business Class (Air Freight; also see C, Economy Class) |
| Y | Yard |
| Y | Yankee (aviation letter code) |
| Y | Yen (Japanese currency) |
| Y | Yukon Territory (postal code designation, Canada) |
| Y | Y Chromosome |
| Y | Bundeswehr (German Armed Forces; number plate) |
| Y | Tyrosine (amino acid) |
| Y | Yaw |
| Y | Yttrium |
| Y | Yeoman |
| Y | Luminance (signal) |
| Y | Consolidated-Vultee Aircraft Corporation (manufacturer's symbol; now Convair) |
| Y | Yotta- (prefix, 10^24 or septillion) |
| Y | Yocto (prefix for one septillionth, 10^ -24) |
| Y | Male Chromosome |
| Y | Yukon Standard Time |
| Y | Search and Rescue Unit (SRU) Error (US DoD) |
| Y | US DoT tire speed rating (188 mph) |
| Y | Vertical axis in Cartesian coordinate system |
| Y | Navigational error of search craft |
| Y | Prototype Aircraft Designation |
