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

• dithering
• dithery
• dithyramb
• dithyrambic
• ditransitive
• ditsy
• dittany
• dittany of crete
• ditto
• ditto mark
• ditty
• ditty bag
• ditz
• ditzy
• diuresis
• diuretic
• diuretic drug
• Diuril
• diurnal
• diurnal parallax
• diurnal variation
• diurnally
• div
• diva
• divagate