| Acronym | Term | Category |
| XA |
Extended Architecture Operation System (SSA) |
General, Health Care |
| XAC |
Cross Reference Account Code |
General |
| XCN |
Executive Control Number |
General |
| XCOM |
External Communications System |
General |
| XDE |
Extended Development Environment |
General |
| XDP |
Extended Data Processing |
General |
| XDR |
Extended Data Representation |
General |
| XID |
Exchange Identifier |
General |
| XIV |
Title 14 Grants to States for Aid to the Permanently & Totally Disabled |
Medicare Beneficiary, Health Care |
| XIX |
Title 19 Grants to States for Medical Assistance Programs (MAA) |
Medicare Beneficiary, Health Care |
| XIXED |
Title 19 Entitlement Date |
Medicare Beneficiary, Health Care |
| XL |
Excelerator (CASE tool software) |
General |
| XLD |
Excelerator Dictionary |
General |
| XMBA |
Executive Masters in Business Administration |
General |
| XMS |
Cross Memory Services |
General |
| XMT |
Transmit |
General |
| XMTL |
Transmittal |
General |
| XQA |
Expanded Quality Assurance |
General |
| XRAN |
Cross Reference Account Number |
General |
| XVI |
Title 16 Grants to States for Aid to the Aged, Blind or Disabled or Aid & Medical Assistance for the |
Medicare Beneficiary, Health Care |
| XVIII |
Title 18 Medicare |
Medicare Beneficiary, Health Care |
| XX |
Title 20 State operated home health care entitlement program |
Medicare Beneficiary, Health Care |
| XXI |
Title 21 State Child Health Program |
Medicare Beneficiary, Health Care |