PMAC which stands for Parallelizable MAC is a Message Authentication Code algorithm. It was created by Phil Rogaway (link: http://www.cs.ucdavis.edu/~rogaway/ocb/pmac.htm).
Essentially PMAC is a method of taking a block cipher and creating an efficient Message Authentication Code that is provably reducible in security to the underlying block cipher.
PMAC is similar in functionality to the OMAC algorithm.