- Xeriscaping: a landscaping method that uses drought-tolerant plants and minimal water.
- Xylocaine: a local anesthetic often used in dentistry and childbirth that belongs to a family of anesthetics known as amino-amides.
- Xylophone: a musical instrument composed of a series of wooden bars that are struck with mallets to produce sound.
- Xylem: the tissue in plants that transports water and nutrients from the roots to the leaves.