1. A radioactive transuranic element; discovered by bombarding americium with helium
   - berkelium, Bk

Type of: metal, metallic element

• phylum Ctenophora
• phylum Cycliophora
• phylum Echinodermata
• phylum Ectoprocta
• phylum Entoprocta
• phylum Mollusca
• phylum Nematoda
• phylum Nemertea
• phylum Nemertina
• phylum Phoronida
• phylum Platyhelminthes
• phylum Pogonophora
• phylum Porifera
• phylum Protozoa
• phylum Pyrrophyta
• phylum Rotifera
• phylum Sipuncula
• physa
• Physalia
• Physalis
• Physalis alkekengi
• Physalis ixocarpa
• Physalis peruviana
• Physalis philadelphica
• Physalis pruinosa