Shihna was a medieval Islamic term meaning, roughly, "military administrator." The term was used particularly for the Seljuk

Seljuq dynasty

The Seljuq ; were a Turco-Persian Sunni Muslim dynasty that ruled parts of Central Asia and the Middle East from the 11th to 14th centuries...

 Turks' representative in Iraq, who exerted the Seljuks' power over the Abbasid caliph. The Seljuks themselves ruled their empire, which included most of southwest Asia

Southwest Asia

Western Asia, West Asia, Southwest Asia or Southwestern Asia are terms that describe the westernmost portion of Asia. The terms are partly coterminous with the Middle East, which describes a geographical position in relation to Western Europe rather than its location within Asia...

in the 11th century and after, from Iran.