what is meant by dominant pole & nondominant pole in the two stage CMOS op-amp circuit & folded cascode OTA circuit?

 

From any point in the s-plane the dominat pole is the one which is closest to that point. The further away a pole is the less effect it has on the system response. See the root locus method originally developed by Evans. Here is the top Google hit

http://www.roymech.co.uk/Related/Control/root_locus.html