The Collaborative International Dictionary of English v.0.48:

Erin \E"rin\ ([=e]"r[i^]n), n. [Ir. Cf. Aryan.]
   An early, and now a poetic, name of Ireland.
   [1913 Webster]

WordNet (r) 3.0 (2006):

Erin
    n 1: an early name of Ireland that is now used in poetry

V.E.R.A. -- Virtual Entity of Relevant Acronyms (February 2016):

ERIN
       Environmental Resources Information Network (Australia, network)


U.S. Gazetteer Places (2000):

Erin, TN -- U.S. city in Tennessee
   Population (2000):    1490
   Housing Units (2000): 653
   Land area (2000):     4.097597 sq. miles (10.612726 sq. km)
   Water area (2000):    0.002284 sq. miles (0.005915 sq. km)
   Total area (2000):    4.099881 sq. miles (10.618641 sq. km)
   FIPS code:            24320
   Located within:       Tennessee (TN), FIPS 47
   Location:             36.316998 N, 87.697946 W
   ZIP Codes (1990):     37061
   Note: some ZIP codes may be omitted esp. for suburbs.
   Headwords:
    Erin, TN
    Erin