| XR | Xylose reductase |
|---|---|
| XR | extended release |
| XRD | X-Ray Diffraction |
| XRD | X-ray diffractometry |
| XRD | X-ray powder diffraction |
| XRE | Xenobiotic responsive element |
| XRE | xenobiotic response element |
| XRF | X-Ray Fluorescence |
| XRII | X-ray image intensifier |
| XRMA | X-ray microanalyses |