Wordnet 3.0
ADJECTIVE (2)
1. 
 characteristic of a region; 
- Example: "regional flora"2. 
 related or limited to a particular region; 
- Example: "a regional dialect"
The Collaborative International Dictionary of English v.0.48:
Regional \Re"gion*al\ (-al), a.
   Of or pertaining to a particular region; sectional.
   [1913 Webster]
WordNet (r) 3.0 (2006):
regional
    adj 1: characteristic of a region; "regional flora"
    2: related or limited to a particular region; "a regional
       dialect"
Moby Thesaurus II by Grady Ward, 1.0:
20 Moby Thesaurus words for "regional":
   areal, cartographic, chorographic, dialect, dialectal, geodetic,
   geographic, geographical, idiomatic, local, locational,
   navigational, positional, provincial, sectional, situal,
   situational, territorial, topographic, zonal