What the difference between spade and neuter?

The term "spade" generally refers to a tool used for digging, while "neuter" is a term used in Biology to describe an animal that has been surgically sterilized, rendering it unable to reproduce. In some contexts, particularly in card games, "spade" also refers to one of the four suits in a deck of playing cards. Thus, the two terms belong to entirely different categories: one is a physical object and the other relates to reproductive status.