ˈpecking ˌorder BrE AmE noun [singular]
a social system within a group of people or animals in which each member knows who has a higher or lower rank than themselves:
Nobody wants to be at the bottom of the pecking order.
PECKING ORDER
Meaning of PECKING ORDER in English
Longman Dictionary of Contemporary English. Longman - Словарь современного английского языка. 2012