1. A radioactive transuranic metallic element; discovered by bombarding uranium with helium atoms
   - americium, Am

Type of: metal, metallic element

• unassignable
• unassigned
• unassisted
• unassuming
• unassumingly
• unassumingness
• unassured
• unasterisked
• unattached
• unattackable
• unattainable
• unattainableness
• unattainably
• unattended
• unattentive
• unattired
• unattractive
• unattractively
• unattractiveness
• unattributable
• unau
• unauthentic
• unauthorised
• unauthorised absence
• unauthorized