"Cal mah" is the Goa'uld word meaning sanctuary. When Apophis escaped from Sokar, he demanded cal mah on Earth. When K'tano chose an isolated forested world to raise his army of Rebel Jaffa in the fight against false gods, he named the planet Cal Mah, a place of sanctuary and a free world for all Jaffa. The simple training camps served as a temporary Rebel base until the planet was attacked from the air by Yu's mothership. The Rebel base was destroyed and the Rebel Jaffa abandoned the planet and fled through the stargate.
Cross Reference: Bra'tac, Goa'uld Language, Imhotep, K'tano, Rak'nor, Rebel Jaffa, Tara'c, Yu
Episode Reference: Serpent's Song, The Warrior