1. A short-lived radioactive metallic element formed from uranium and disintegrating into actinium and then into lead
   - protactinium, protoactinium, Pa

Type of: metal, metallic element

• astereognosis
• Asterias
• asteriated
• asterid dicot family
• asterid dicot genus
• Asteridae
• asterion
• asterisk
• asterisked
• asterism
• asterismal
• astern
• asternal
• asteroid
• asteroid belt
• asteroidal
• Asteroidea
• Asterope
• asthenia
• asthenic
• asthenic type
• asthenopia
• asthenosphere
• astheny
• asthma