Definition of riggon in US English:

riggon

noun

rare, historical
  • A ram having only one testicle, or only one testicle descended.

Origin

Mid 16th century. Apparently ultimately from rig, although the origin of the ending is uncertain. With the same sense compare earlier rig, riggald, slightly earlier riggot, rigling, and also ridgel, ridgeling. For the likely semantic motivation of these words, see rig.

Pronunciation

riggon

/ˈrɪɡən/