| Xta | chiasmata |
|---|---|
| Xtab | cross-tabulating |
| XTC | Ecstasy (MDMA; 3,4-Methylenedioxymethamphetamine) |
| XTE | xeroderma, talipes, and enamel defect [syndrome] |
| XTM | xanthoma tuberosum multiplex |
| XTP | xanthosine triphosphate |
| XU | excretory urogram; X unit |
| Xu | X-unit |
| Xu5P, | Xu5p xylulose-5-phosphate |
| XuMP | xylulose monophosphate |