1. A soft silvery metallic element of the rare earth group having no stable isotope; was discovered in radioactive form as a fission product of uranium
   - promethium, Pm

Type of: metal, metallic element

• only if
• only too
• only when
• Ono
• Onobrychis
• Onobrychis viciaefolia
• Onobrychis viciifolia
• Onoclea
• Onoclea sensibilis
• Onoclea struthiopteris
• onomancer
• onomancy
• onomastic
• onomasticon
• onomastics
• onomatomania
• onomatopoeia
• onomatopoeic
• onomatopoeical
• onomatopoetic
• Onondaga
• Ononis
• Ononis repens
• Ononis spinosa
• Onopordon