Definition of "tetrarch" in English

noun

1. A governor or ruler of a quarter of a country, especially of a fourth part of a province in or client state of Ancient Rome.

2. Each of the four members of a jointly ruling tetrarchy, notably of the Roman Empire since Diocletian.

3. An officer in charge of a fourth part of a phalanx in Ancient Greece.

adjective

1. (botany) Having four vascular strands in a fibrovascular cylinder or stele.