تحالفوا عَلَى كَذَا

They swore, one to another, respecting, or to do, such a thing; as also ↓ احتلفوا. (TA.)

And تحالفوا (tropical:) They confederated; or united in a confederacy, league, compact, or covenant. (S. K, TA.) And تحالفا (assumed tropical:) They two united in a confederacy &c. that their case should be one in respect of aiding and defending. (Msb.) And تحالفا بِالأَيْمَانِ أَنْ يَكُونَ أَمْرُهُمَا وَاحِدًا (assumed tropical:) They two united in a confederacy &c., by oaths, that their case should be one. (Lth, TA.)