Palmer Archipelago Formerly Antarctic Archipelago. An island group of Antarctica off the northwest coast of Graham Land. The islands are part of the British Antarctic Territory but are also claimed by Chile and Argentina.American Heritage® Dictionary of the English Language, Fifth Edition. Copyright © 2016 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.Palmer Archipelago n (Placename) a group of islands between South America and Antarctica: part of the British Antarctic Territory, formerly the British colony of the Falkland Islands and Dependencies. (Claims are suspended under the Antarctic Treaty). Former name: Antarctic Archipelago Collins English Dictionary ? Complete and Unabridged, 12th Edition 2014 © HarperCollins Publishers 1991, 1994, 1998, 2000, 2003, 2006, 2007, 2009, 2011, 2014