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

• skin sensation
• skin senses
• skin test
• skin tumor
• skin tumour
• skin-deep
• skin-dive
• skin-diver
• skincare
• skinflint
• skinful
• skinhead
• skinheads
• skink
• skinless
• skinned
• skinner
• Skinnerian
• skinniness
• skinny
• skinny-dip
• skinny-dipper
• skint
• skintight
• skip