From Robert Jordan's Fantasy novel series "The Wheel of Time":
Societies among the Aes Sedai, seven in number and designated by colors: Blue, Red, White, Green, Brown, Yellow and Gray. All Aes Sedai except the Amyrlin Seat belong to one. Each follows a specific philosophy of the use of the One Power and the purpose of the Aes Sedai. The Red Ajah bends its energies to finding men who can channel, and to gentling them. The Brown forsakes involvement with the mundane world and dedicates itself to seeking knowledge, while the White, largely eschewing both the world and the value of worldly knowledge, devotes itself to questions of philosophy and truth. The Green Ajah (called the Battle Ajah during the Trolloc Wars) holds itself ready for Tarmon Gai'don, the Yellow concentrates on the study of Healing, and Blue sisters involve themselves with causes and justice. The Gray are mediators, seeking harmony and consenus. Rumors of a Black Ajah, dedicated to serving the Dark One, are offically denied. However, it is understood that this sect does exist, as members of all Ajahs secretly, having sold their souls to the Dark One for a place in ruling the world.
Moiraine is a member of the Blue Ajah, and is a close ally to the Amyrlin Seat, working directly for the cause of defending the world from the clutches of the Dark One.
Ajah is a word used when cheering someone on in something which they have not yet attained.
"The crowd raised their glasses to the losing team they were cheering for and shouted "AJAH!". "Its time to wake up boys"
The husband was unsure he could do something but his wife with faith in him said "Ajah, you can do it"