Singular
platypus

Plural
platypuses or platypi

 
A platypus
  1. (countable) A platypus is an animal that lives on both water and land. It has a body like a mole, a bill like a duck, a tail like a beaver, a waterproof pelt, and webbed feet. A male platypus has poisonous spurs on the inside of the back legs.