The Collaborative International Dictionary of English v.0.48:

Algonquin \Al*gon"quin\, Algonkin \Al*gon"kin\, prop. n.
   One of a widely spread family of Indians, including many
   distinct tribes, which formerly occupied most of the northern
   and eastern part of North America. The name was originally
   applied to a group of Indian tribes north of the River St.
   Lawrence.
   [1913 Webster]

WordNet (r) 3.0 (2006):

Algonquin
    adj 1: of or relating to an Algonquian tribe or its people or
           language [syn: Algonquian, Algonkian, Algonquin]
    n 1: a member of any of the North American Indian groups
         speaking an Algonquian language and originally living in
         the subarctic regions of eastern Canada; many Algonquian
         tribes migrated south into the woodlands from the
         Mississippi River to the Atlantic coast [syn: Algonquian,
         Algonquin]
    2: family of North American Indian languages spoken from
       Labrador to South Carolina and west to the Great Plains [syn:
       Algonquian, Algonquin, Algonquian language]