1. Having three atoms; - said of certain elements or radicals 
2. Having a valence of three; trivalent; sometimes, in a specific sense, having three hydroxyl groups, whether acid or basic

Encyclopedia: Triatomic

• xenogenesis
• xenograft
• xenolith
• xenon
• Xenophanes
• xenophobe
• xenophobia
• xenophobic
• Xenophon
• Xenopodidae
• Xenopus
• Xenopus laevis
• Xenorhyncus
• Xenorhyncus asiaticus
• Xenosauridae
• Xenosaurus
• xenotime
• xenotransplant
• xenotransplantation
• xeranthemum
• Xeranthemum annuum
• xeric
• xeriscape
• xeriscaping
• Xerobates