Final answer:
Osman was referred to as "Othman" in the West and his followers were called Ottomans.
Step-by-step explanation:
The person who was referred to as "Othman" in the West and whose followers were called Ottomans was A. Osman. The Ottoman Empire was named after Osman I, who founded the empire in the 14th century. The Ottomans were a Turkish dynasty that expanded their territory over the years and eventually conquered the city of Constantinople, which became their capital.