Rosh timer / Roshdi:

Rosh timer, or Roshdi, is the informal countdown and timing information teams use to track Roshan’s respawn window in Dota 2.

Because Roshan drops the Aegis of the Immortal and other key rewards, knowing when he is likely to be alive again helps teams plan smoke ganks, warding, map control, and objective pushes. The term can refer either to the moment Roshan died or to the approximate time he may respawn, since his reappearance is not exact and must be checked in-game with vision or by contesting the pit. For example, if Roshan died after a team fight, allies may say “watch Rosh timer” so supports can place deep wards near the pit before the enemy arrives to take Aegis uncontested.

Related: Roshan, Aegis of the Immortal, Ward, Map Control