| X-A | xylene and alcohol |
|---|---|
| X-CGD | X-linked chronic granulomatous disease |
| X-mas | Christmas [factor] |
| x-mat | crossmatch [blood] |
| X-match | crossmatch |
| x-rays | roentgen rays |
| X-sect | cross-section |
| X-TEP | crossed immunoelectrophoresis |
| X/S | cross-section |
| X3 | orientation as to time, place, and person |