A more thorough explanation:

Dyarchy (pronounced dI-ahr-kee) is a form of government where two people share the ruling power. The word comes from the Greek words "dy" meaning "two" and "archein" meaning "rule".

• William and Mary of England jointly ruled the country as a dyarchy.
• In India, the Government of India Act, 1919 introduced a system of dyarchy where the provincial executives were divided into two sections - authoritarian and popularly responsible. The authoritarian section was composed of councillors appointed by the Crown, while the popularly responsible section was composed of ministers appointed by the governor and responsible to the provincial legislative councils.

The examples illustrate how dyarchy involves two people sharing the ruling power. In the case of William and Mary, they jointly ruled England as a dyarchy. In the case of India, the provincial executives were divided into two sections, each with different levels of authority and responsibility.