Choose the one-word term that best describes the definition below.

A government formed after armed forces remove the existing civilian leadership and assume authority.

The correct option is Junta.

Step-by-Step Explanation:

1. Analyzing the Given Definition:
The definition provided refers to a scenario where armed forces (the military) overthrow and remove an established civilian government to seize political power and assume governing authority over a nation. This action is historically referred to as a military coup d'état.

2. Evaluating the Options:
- Junta: A junta (specifically a military junta) is a committee or group of military officers who rule a country after seizing control through force. This directly matches the definition.
- Theocracy: A system of government ruled by religious officials or based on religious authority and laws, rather than military power.
- Meritocracy: A system in which individuals hold authority or advance based on demonstrated ability, skill, and merit, rather than military force or inheritance.
- Monarchy: A form of government ruled by a monarch (such as a king, queen, or emperor), where supreme authority is typically passed down through a hereditary lineage.

3. Conclusion:
The precise one-word term for a government formed after military forces take over power from civilian leadership is a Junta.