The Collaborative International Dictionary of English v.0.48:

Augustinian \Au`gus*tin"i*an\, a.
   Of or pertaining to St. Augustine, bishop of Hippo in
   Northern Africa (b. 354 -- d. 430), or to his doctrines.
   [1913 Webster]

   Augustinian canons, an order of monks once popular in
      England and Ireland; -- called also regular canons of St.
      Austin, and black canons.

   Augustinian hermits or Austin friars, an order of friars
      established in 1265 by Pope Alexander IV. It was
      introduced into the United States from Ireland in 1790.

   Augustinian nuns, an order of nuns following the rule of
      St. Augustine.

   Augustinian rule, a rule for religious communities based
      upon the 109th letter of St. Augustine, and adopted by the
      Augustinian orders.
      [1913 Webster]

WordNet (r) 3.0 (2006):

Austin Friars
    n 1: an Augustinian monastic order