According to Wikipedia, A set of states C is a communicating class if every pair of states in C communicates with each other. A communicating class is closed if the probability of leaving the class is zero.
Would you call an absorbing state a closed communicating class since it cannot be left and it communicates with itself?
However, one problem with calling an absorbing state a closed communicating class is that since it consists of only one state (obviously) - and this might not satisfy the definition of a set of states.