soleus Syllabification: (so·le·us)Pronunciation: /ˈsōlēəs/ (also soleus muscle)Definition of soleus noun Anatomy a broad muscle in the lower calf, below the gastrocnemius, that flexes the foot to point the toes downward. Origin: late 17th century: modern Latin, from Latin solea 'sole'soleus in other Oxford dictionaries Definition of soleus in the British & World English dictionary